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Why Residents Order Unnecessary Inpatient Laboratory Tests
Resident physicians routinely order inpatient laboratory tests,[1] and there is evidence to suggest that many of these tests are unnecessary[2] and potentially harmful.[3] The Society of Hospital Medicine has identified reducing the unnecessary ordering of inpatient laboratory testing as part of the Choosing Wisely campaign.[4] Hospitalists at academic medical centers face growing pressures to develop processes to reduce low‐value care and train residents to be stewards of healthcare resources.[5] Studies[6, 7, 8, 9] have described that institutional and training factors drive residents' resource utilization patterns, but, to our knowledge, none have described what factors contribute to residents' unnecessary laboratory testing. To better understand the factors associated with residents' ordering patterns, we conducted a qualitative analysis of internal medicine (IM) and general surgery (GS) residents at a large academic medical center in order to describe residents' perception of the: (1) frequency of ordering unnecessary inpatient laboratory tests, (2) factors contributing to that behavior, and (3) potential interventions to change it. We also explored differences in responses by specialty and training level.
METHODS
In October 2014, we surveyed all IM and GS residents at the Hospital of the University of Pennsylvania. We reviewed the literature and conducted focus groups with residents to formulate items for the survey instrument. A draft of the survey was administered to 8 residents from both specialties, and their feedback was collated and incorporated into the final version of the instrument. The final 15‐question survey was comprised of 4 components: (1) training information such as specialty and postgraduate year (PGY), (2) self‐reported frequency of perceived unnecessary ordering of inpatient laboratory tests, (3) perception of factors contributing to unnecessary ordering, and (4) potential interventions to reduce unnecessary ordering. An unnecessary test was defined as a test that would not change management regardless of its result. To increase response rates, participants were entered into drawings for $5 gift cards, a $200 air travel voucher, and an iPad mini.
Descriptive statistics and 2tests were conducted with Stata version 13 (StataCorp LP, College Station, TX) to explore differences in the frequency of responses by specialty and training level. To identify themes that emerged from free‐text responses, two independent reviewers (M.S.S. and E.J.K.) performed qualitative content analysis using grounded theory.[10] Reviewers read 10% of responses to create a coding guide. Another 10% of the responses were randomly selected to assess inter‐rater reliability by calculating scores. The reviewers independently coded the remaining 80% of responses. Discrepancies were adjudicated by consensus between the reviewers. The University of Pennsylvania Institutional Review Board deemed this study exempt from review.
RESULTS
The sample comprised 57.0% (85/149) of IM and 54.4% (31/57) of GS residents (Table 1). Among respondents, perceived unnecessary inpatient laboratory test ordering was self‐reported by 88.2% of IM and 67.7% of GS residents. This behavior was reported to occur on a daily basis by 43.5% and 32.3% of responding IM and GS residents, respectively. Across both specialties, the most commonly reported factors contributing to these behaviors were learned practice habit/routine (90.5%), a lack of understanding of the costs associated with lab tests (86.2%), diagnostic uncertainty (82.8%), and fear of not having the lab result information when requested by an attending (75.9%). There were no significant differences in any of these contributing factors by specialty or PGY level. Among respondents who completed a free‐text response (IM: 76 of 85; GS: 21 of 31), the most commonly proposed interventions to address these issues were increasing cost transparency (IM 40.8%; GS 33.3%), improvements to faculty role modeling (IM 30.2%; GS 33.3%), and computerized reminders or decision support (IM 21.1%; GS 28.6%) (Table 2).
| Residents (n = 116)* | |
|---|---|
| |
| Reported he or she orders unnecessary routine labs, no. (%) | 96 (82.8) |
| Frequency of ordering unnecessary labs, no. (%) | |
| Daily | 47 (49.0) |
| 23 times/week | 44 (45.8) |
| 1 time/week or less | 5 (5.2) |
| Agreement with statement as factors contributing to ordering unnecessary labs, no. (%) | |
| Practice habit; I am trained to order repeating daily labs | 105 (90.5) |
| Lack of cost transparency of labs | 100 (86.2) |
| Discomfort with diagnostic uncertainty | 96 (82.8) |
| Concern that the attending will ask for the data and I will not have it | 88 (75.9) |
| Lack of role modeling of cost conscious care | 78 (67.2) |
| Lack of cost conscious culture at our institution | 76 (65.5) |
| Lack of experience | 72 (62.1) |
| Ease of ordering repeating labs in EHR | 60 (51.7) |
| Fear of litigation from missed diagnosis related to lab data | 44 (37.9) |
| Categories* | Representative Quotes | IM, n = 76, No. (%) | GS, n = 21, No. (%) |
|---|---|---|---|
| |||
| Cost transparency | Let us know the costs of what we order and train us to remember that a patient gets a bill and we are contributing to a possible bankruptcy or hardship. | 31 (40.8) | 7 (33.3) |
| Display the cost of labs when [we're] ordering them [in the EHR]. | |||
| Post the prices so that MDs understand how much everything costs. | |||
| Role modeling restrain | Train attendings to be more critical about necessity of labs and overordering. Make it part of rounding practice to decide on the labs truly needed for each patient the next day. | 23 (30.2) | 7 (33.3) |
| Attendings could review daily lab orders and briefly explain which they do not believe we need. This would allow residents to learn from their experience and their thought processes. | |||
| Encouragement and modeling of this practice from the faculty perhaps by laying out more clear expectations for which clinical situations warrant daily labs and which do not. | |||
| Computerized or decision support | When someone orders labs and the previous day's lab was normal or labs were stable for 2 days, an alert should pop up to reconsider. | 16 (21.1) | 6 (28.6) |
| Prevent us from being able to order repeating [or standing] labs. | |||
| Track how many times labs changed management, and restrict certain labslike LFTs/coags. | |||
| High‐value care educational curricula | Increase awareness of issue by having a noon conference about it or some other forum for residents to discuss the issue. | 12 (15.8) | 4 (19.0) |
| Establish guidelines for housestaff to learn/follow from start of residency. | |||
| Integrate cost conscious care into training program curricula. | |||
| System improvements | Make it easier to get labs later [in the day] | 6 (7.9) | 2 (9.5) |
| Improve timeliness of phlebotomy/laboratory systems. | |||
| More responsive phlebotomy. | |||
DISCUSSION
A significant portion of inpatient laboratory testing is unnecessary,[2] creating an opportunity to reduce utilization and associated costs. Our findings demonstrate that these behaviors occur at high levels among residents (IM 88.2%; GS 67.7%) at a large academic medical center. These findings also reveal that residents attribute this behavior to practice habit, lack of access to cost data, and perceived expectations for daily lab ordering by faculty. Interventions to change these behaviors will need to involve changes to the health system culture, increasing transparency of the costs associated with healthcare services, and shifting to a model of education that celebrates restraint.[11]
Our study adds to the emerging quest for delivering value in healthcare and provides several important insights for hospitalists and medical educators at academic centers. First, our findings reflect the significant role that the clinical learning environment plays in influencing practice behaviors among residents. Residency training is a critical time when physicians begin to form habits that imprint upon their future practice patterns,[5] and our residents are aware that their behavior to order what they perceive to be unnecessary laboratory tests is driven by habit. Studies[6, 7] have shown that residents may implicitly accept certain styles of practice as correct and are more likely to adopt those styles during the early years of their training. In our institution, for example, the process of ordering standing or daily morning labs using a repeated copy‐forward function in the electronic health record is a common, learned practice (a ritual) that is passed down from senior to junior residents year after year. This practice is common across both training specialties. There is a need to better understand, measure, and change the culture in the clinical learning environment to demonstrate practices and values that model high‐value care for residents. Multipronged interventions that address culture, oversight, and systems change[12] are necessary to facilitate effective physician stewardship of inpatient laboratory testing and attack a problem so deeply ingrained in habit.
Second, residents in our study believe that access to cost information will better equip them to reduce unnecessary lab ordering. Two recent systematic reviews[13, 14] have shown that having real‐time access to charges changes physician ordering and prescribing behavior. Increasing cost transparency may not only be an important intervention for hospitals to reduce overuse and control cost, but also better arm resident physicians with the information they need to make higher‐value recommendations for their patients and be stewards of healthcare resources.
Third, our study highlights that residents' unnecessary laboratory utilization is driven by perceived, unspoken expectations for such ordering by faculty. This reflects an important undercurrent in the medical education system that has historically emphasized and rewarded thoroughness while often penalizing restraint.[11] Hospitalists can play a major role in changing these behaviors by sharing their expectations regarding test ordering at the beginning of teaching rotations, including teaching points that discourage overutilization during rounds, and role modeling high‐value care in their own practice. Taken together and practiced routinely, these hospitalist behaviors could prevent poor habits from forming in our trainees and discourage overinvestigation. Hospitalists must be responsible to disseminate the practice of restraint to achieve more cost‐effective care. Purposeful faculty development efforts in the area of high‐value care are needed. Additionally, supporting physician leaders that serve as the institutional bridge between graduate medical education and the health system[15] could foster an environment conducive to coaching residents and faculty to reduce unnecessary practice variation.
This study is subject to several limitations. First, the survey was conducted at a single academic medical center, with a modest response rate, and thus our findings may not be generalizable to other settings or residents of different training programs. Second, we did not validate residents' perception of whether or not tests were, in fact, unnecessary. We also did not validate residents' self‐reporting of their own behavior, which may vary from actual behavior. Lack of validation at the level of the tests and at the level of the residents' behavior are two distinct but inter‐related limitations. Although self‐reported responses among residents are an important indicator of their practice, validating these data with objective measures, such as a measure of necessity of ordered lab tests as determined by an expert physician or group of experienced physicians or the number of inpatient labs ordered by residents, may add further insights. Ordering of perceived unnecessary tests may be even more common if there was under‐reporting of this behavior. Third, although we provided a definition within the survey, interpretation among survey respondents of the term unnecessary may vary, and this variation may contribute to our findings. However, we did provide a clear definition in the survey and we attempted to mitigate this with feedback from residents on our preliminary pilot.
In conclusion, this is one of the first qualitative evaluations to explore residents' perceptions on why they order unnecessary inpatient laboratory tests. Our findings offer a rich understanding of residents' beliefs about their own role in unnecessary lab ordering and explore possible solutions through the lens of the resident. Yet, it is unclear whether tests deemed unnecessary by residents would also be considered unnecessary by attending physicians or even patients. Future efforts are needed to better define which inpatient tests are unnecessary from multiple perspectives including clinicians and patients.
Acknowledgements
The authors thank Patrick J. Brennan, MD, Jeffery S. Berns, MD, Lisa M. Bellini, MD, Jon B. Morris, MD, and Irving Nachamkin, DrPH, MPH, all from the Hospital of the University of Pennsylvania, for supporting this work. They received no compensation.
Disclosures: This work was presented in part at the AAMC Integrating Quality Meeting, June 11, 2015, Chicago, Illinois; and the Alliance for Academic Internal Medicine Fall Meeting, October 9, 2015, Atlanta, Georgia. The authors report no conflicts of interest.
- , , , . The impact of residents, interns, and attendings on inpatient laboratory ordering patterns: a report from one university's hospitalist service. Acad Med. 2011;86(1):139–145.
- , , , , . The landscape of inappropriate laboratory testing: a 15‐year meta‐analysis. PLoS One. 2013;8(11):e78962.
- , , , et al. Diagnostic blood loss from phlebotomy and hospital‐acquired anemia during acute myocardial infarction. Arch Intern Med. 2011;171(18):1646–1653.
- , , , et al. Choosing wisely in adult hospital medicine: five opportunities for improved healthcare value. J Hosp Med. 2013;8(9):486–492.
- . Charting the route to high‐value care the role of medical education. JAMA. 2016;314(22):2359–2361.
- , , , , . Spending patterns in region of residency training and subsequent expenditures for care provided by practicing physicians for Medicare beneficiaries. JAMA. 2014;312(22):2385–2393.
- , , , . The association between residency training and internists' ability to practice conservatively. JAMA Intern Med. 2014;174(10):1640–1648.
- , , , , . Effect of attending practice style on generic medication prescribing by residents in the clinic setting: an observational study. J Gen Intern Med. 2015;30(9):1286–1293.
- , , , . Role‐modeling cost‐conscious care—a national evaluation of perceptions of faculty at teaching hospitals in the United States. J Gen Intern Med. 2015;30(9):1294–1298.
- , . The discovery of grounded theory. Int J Qual Methods. 1967;5:1–10.
- , . A new model for medical education: celebrating restraint. JAMA. 2012;308(13):1329–1330.
- , , . A framework for the frontline: how hospitalists can improve healthcare value. J Hosp Med. 2016;11(4):297–302.
- , , , . The effect of charge display on cost of care and physician practice behaviors: a systematic review. J Gen Intern Med. 2015;30(6):835–842.
- , , , . Impact of price display on provider ordering: a systematic review. J Hosp Med. 2016;11(1):65–76.
- , . Merging the health system and education silos to better educate future physicians. JAMA. 2015;314(22):2349–2350.
Resident physicians routinely order inpatient laboratory tests,[1] and there is evidence to suggest that many of these tests are unnecessary[2] and potentially harmful.[3] The Society of Hospital Medicine has identified reducing the unnecessary ordering of inpatient laboratory testing as part of the Choosing Wisely campaign.[4] Hospitalists at academic medical centers face growing pressures to develop processes to reduce low‐value care and train residents to be stewards of healthcare resources.[5] Studies[6, 7, 8, 9] have described that institutional and training factors drive residents' resource utilization patterns, but, to our knowledge, none have described what factors contribute to residents' unnecessary laboratory testing. To better understand the factors associated with residents' ordering patterns, we conducted a qualitative analysis of internal medicine (IM) and general surgery (GS) residents at a large academic medical center in order to describe residents' perception of the: (1) frequency of ordering unnecessary inpatient laboratory tests, (2) factors contributing to that behavior, and (3) potential interventions to change it. We also explored differences in responses by specialty and training level.
METHODS
In October 2014, we surveyed all IM and GS residents at the Hospital of the University of Pennsylvania. We reviewed the literature and conducted focus groups with residents to formulate items for the survey instrument. A draft of the survey was administered to 8 residents from both specialties, and their feedback was collated and incorporated into the final version of the instrument. The final 15‐question survey was comprised of 4 components: (1) training information such as specialty and postgraduate year (PGY), (2) self‐reported frequency of perceived unnecessary ordering of inpatient laboratory tests, (3) perception of factors contributing to unnecessary ordering, and (4) potential interventions to reduce unnecessary ordering. An unnecessary test was defined as a test that would not change management regardless of its result. To increase response rates, participants were entered into drawings for $5 gift cards, a $200 air travel voucher, and an iPad mini.
Descriptive statistics and 2tests were conducted with Stata version 13 (StataCorp LP, College Station, TX) to explore differences in the frequency of responses by specialty and training level. To identify themes that emerged from free‐text responses, two independent reviewers (M.S.S. and E.J.K.) performed qualitative content analysis using grounded theory.[10] Reviewers read 10% of responses to create a coding guide. Another 10% of the responses were randomly selected to assess inter‐rater reliability by calculating scores. The reviewers independently coded the remaining 80% of responses. Discrepancies were adjudicated by consensus between the reviewers. The University of Pennsylvania Institutional Review Board deemed this study exempt from review.
RESULTS
The sample comprised 57.0% (85/149) of IM and 54.4% (31/57) of GS residents (Table 1). Among respondents, perceived unnecessary inpatient laboratory test ordering was self‐reported by 88.2% of IM and 67.7% of GS residents. This behavior was reported to occur on a daily basis by 43.5% and 32.3% of responding IM and GS residents, respectively. Across both specialties, the most commonly reported factors contributing to these behaviors were learned practice habit/routine (90.5%), a lack of understanding of the costs associated with lab tests (86.2%), diagnostic uncertainty (82.8%), and fear of not having the lab result information when requested by an attending (75.9%). There were no significant differences in any of these contributing factors by specialty or PGY level. Among respondents who completed a free‐text response (IM: 76 of 85; GS: 21 of 31), the most commonly proposed interventions to address these issues were increasing cost transparency (IM 40.8%; GS 33.3%), improvements to faculty role modeling (IM 30.2%; GS 33.3%), and computerized reminders or decision support (IM 21.1%; GS 28.6%) (Table 2).
| Residents (n = 116)* | |
|---|---|
| |
| Reported he or she orders unnecessary routine labs, no. (%) | 96 (82.8) |
| Frequency of ordering unnecessary labs, no. (%) | |
| Daily | 47 (49.0) |
| 23 times/week | 44 (45.8) |
| 1 time/week or less | 5 (5.2) |
| Agreement with statement as factors contributing to ordering unnecessary labs, no. (%) | |
| Practice habit; I am trained to order repeating daily labs | 105 (90.5) |
| Lack of cost transparency of labs | 100 (86.2) |
| Discomfort with diagnostic uncertainty | 96 (82.8) |
| Concern that the attending will ask for the data and I will not have it | 88 (75.9) |
| Lack of role modeling of cost conscious care | 78 (67.2) |
| Lack of cost conscious culture at our institution | 76 (65.5) |
| Lack of experience | 72 (62.1) |
| Ease of ordering repeating labs in EHR | 60 (51.7) |
| Fear of litigation from missed diagnosis related to lab data | 44 (37.9) |
| Categories* | Representative Quotes | IM, n = 76, No. (%) | GS, n = 21, No. (%) |
|---|---|---|---|
| |||
| Cost transparency | Let us know the costs of what we order and train us to remember that a patient gets a bill and we are contributing to a possible bankruptcy or hardship. | 31 (40.8) | 7 (33.3) |
| Display the cost of labs when [we're] ordering them [in the EHR]. | |||
| Post the prices so that MDs understand how much everything costs. | |||
| Role modeling restrain | Train attendings to be more critical about necessity of labs and overordering. Make it part of rounding practice to decide on the labs truly needed for each patient the next day. | 23 (30.2) | 7 (33.3) |
| Attendings could review daily lab orders and briefly explain which they do not believe we need. This would allow residents to learn from their experience and their thought processes. | |||
| Encouragement and modeling of this practice from the faculty perhaps by laying out more clear expectations for which clinical situations warrant daily labs and which do not. | |||
| Computerized or decision support | When someone orders labs and the previous day's lab was normal or labs were stable for 2 days, an alert should pop up to reconsider. | 16 (21.1) | 6 (28.6) |
| Prevent us from being able to order repeating [or standing] labs. | |||
| Track how many times labs changed management, and restrict certain labslike LFTs/coags. | |||
| High‐value care educational curricula | Increase awareness of issue by having a noon conference about it or some other forum for residents to discuss the issue. | 12 (15.8) | 4 (19.0) |
| Establish guidelines for housestaff to learn/follow from start of residency. | |||
| Integrate cost conscious care into training program curricula. | |||
| System improvements | Make it easier to get labs later [in the day] | 6 (7.9) | 2 (9.5) |
| Improve timeliness of phlebotomy/laboratory systems. | |||
| More responsive phlebotomy. | |||
DISCUSSION
A significant portion of inpatient laboratory testing is unnecessary,[2] creating an opportunity to reduce utilization and associated costs. Our findings demonstrate that these behaviors occur at high levels among residents (IM 88.2%; GS 67.7%) at a large academic medical center. These findings also reveal that residents attribute this behavior to practice habit, lack of access to cost data, and perceived expectations for daily lab ordering by faculty. Interventions to change these behaviors will need to involve changes to the health system culture, increasing transparency of the costs associated with healthcare services, and shifting to a model of education that celebrates restraint.[11]
Our study adds to the emerging quest for delivering value in healthcare and provides several important insights for hospitalists and medical educators at academic centers. First, our findings reflect the significant role that the clinical learning environment plays in influencing practice behaviors among residents. Residency training is a critical time when physicians begin to form habits that imprint upon their future practice patterns,[5] and our residents are aware that their behavior to order what they perceive to be unnecessary laboratory tests is driven by habit. Studies[6, 7] have shown that residents may implicitly accept certain styles of practice as correct and are more likely to adopt those styles during the early years of their training. In our institution, for example, the process of ordering standing or daily morning labs using a repeated copy‐forward function in the electronic health record is a common, learned practice (a ritual) that is passed down from senior to junior residents year after year. This practice is common across both training specialties. There is a need to better understand, measure, and change the culture in the clinical learning environment to demonstrate practices and values that model high‐value care for residents. Multipronged interventions that address culture, oversight, and systems change[12] are necessary to facilitate effective physician stewardship of inpatient laboratory testing and attack a problem so deeply ingrained in habit.
Second, residents in our study believe that access to cost information will better equip them to reduce unnecessary lab ordering. Two recent systematic reviews[13, 14] have shown that having real‐time access to charges changes physician ordering and prescribing behavior. Increasing cost transparency may not only be an important intervention for hospitals to reduce overuse and control cost, but also better arm resident physicians with the information they need to make higher‐value recommendations for their patients and be stewards of healthcare resources.
Third, our study highlights that residents' unnecessary laboratory utilization is driven by perceived, unspoken expectations for such ordering by faculty. This reflects an important undercurrent in the medical education system that has historically emphasized and rewarded thoroughness while often penalizing restraint.[11] Hospitalists can play a major role in changing these behaviors by sharing their expectations regarding test ordering at the beginning of teaching rotations, including teaching points that discourage overutilization during rounds, and role modeling high‐value care in their own practice. Taken together and practiced routinely, these hospitalist behaviors could prevent poor habits from forming in our trainees and discourage overinvestigation. Hospitalists must be responsible to disseminate the practice of restraint to achieve more cost‐effective care. Purposeful faculty development efforts in the area of high‐value care are needed. Additionally, supporting physician leaders that serve as the institutional bridge between graduate medical education and the health system[15] could foster an environment conducive to coaching residents and faculty to reduce unnecessary practice variation.
This study is subject to several limitations. First, the survey was conducted at a single academic medical center, with a modest response rate, and thus our findings may not be generalizable to other settings or residents of different training programs. Second, we did not validate residents' perception of whether or not tests were, in fact, unnecessary. We also did not validate residents' self‐reporting of their own behavior, which may vary from actual behavior. Lack of validation at the level of the tests and at the level of the residents' behavior are two distinct but inter‐related limitations. Although self‐reported responses among residents are an important indicator of their practice, validating these data with objective measures, such as a measure of necessity of ordered lab tests as determined by an expert physician or group of experienced physicians or the number of inpatient labs ordered by residents, may add further insights. Ordering of perceived unnecessary tests may be even more common if there was under‐reporting of this behavior. Third, although we provided a definition within the survey, interpretation among survey respondents of the term unnecessary may vary, and this variation may contribute to our findings. However, we did provide a clear definition in the survey and we attempted to mitigate this with feedback from residents on our preliminary pilot.
In conclusion, this is one of the first qualitative evaluations to explore residents' perceptions on why they order unnecessary inpatient laboratory tests. Our findings offer a rich understanding of residents' beliefs about their own role in unnecessary lab ordering and explore possible solutions through the lens of the resident. Yet, it is unclear whether tests deemed unnecessary by residents would also be considered unnecessary by attending physicians or even patients. Future efforts are needed to better define which inpatient tests are unnecessary from multiple perspectives including clinicians and patients.
Acknowledgements
The authors thank Patrick J. Brennan, MD, Jeffery S. Berns, MD, Lisa M. Bellini, MD, Jon B. Morris, MD, and Irving Nachamkin, DrPH, MPH, all from the Hospital of the University of Pennsylvania, for supporting this work. They received no compensation.
Disclosures: This work was presented in part at the AAMC Integrating Quality Meeting, June 11, 2015, Chicago, Illinois; and the Alliance for Academic Internal Medicine Fall Meeting, October 9, 2015, Atlanta, Georgia. The authors report no conflicts of interest.
Resident physicians routinely order inpatient laboratory tests,[1] and there is evidence to suggest that many of these tests are unnecessary[2] and potentially harmful.[3] The Society of Hospital Medicine has identified reducing the unnecessary ordering of inpatient laboratory testing as part of the Choosing Wisely campaign.[4] Hospitalists at academic medical centers face growing pressures to develop processes to reduce low‐value care and train residents to be stewards of healthcare resources.[5] Studies[6, 7, 8, 9] have described that institutional and training factors drive residents' resource utilization patterns, but, to our knowledge, none have described what factors contribute to residents' unnecessary laboratory testing. To better understand the factors associated with residents' ordering patterns, we conducted a qualitative analysis of internal medicine (IM) and general surgery (GS) residents at a large academic medical center in order to describe residents' perception of the: (1) frequency of ordering unnecessary inpatient laboratory tests, (2) factors contributing to that behavior, and (3) potential interventions to change it. We also explored differences in responses by specialty and training level.
METHODS
In October 2014, we surveyed all IM and GS residents at the Hospital of the University of Pennsylvania. We reviewed the literature and conducted focus groups with residents to formulate items for the survey instrument. A draft of the survey was administered to 8 residents from both specialties, and their feedback was collated and incorporated into the final version of the instrument. The final 15‐question survey was comprised of 4 components: (1) training information such as specialty and postgraduate year (PGY), (2) self‐reported frequency of perceived unnecessary ordering of inpatient laboratory tests, (3) perception of factors contributing to unnecessary ordering, and (4) potential interventions to reduce unnecessary ordering. An unnecessary test was defined as a test that would not change management regardless of its result. To increase response rates, participants were entered into drawings for $5 gift cards, a $200 air travel voucher, and an iPad mini.
Descriptive statistics and 2tests were conducted with Stata version 13 (StataCorp LP, College Station, TX) to explore differences in the frequency of responses by specialty and training level. To identify themes that emerged from free‐text responses, two independent reviewers (M.S.S. and E.J.K.) performed qualitative content analysis using grounded theory.[10] Reviewers read 10% of responses to create a coding guide. Another 10% of the responses were randomly selected to assess inter‐rater reliability by calculating scores. The reviewers independently coded the remaining 80% of responses. Discrepancies were adjudicated by consensus between the reviewers. The University of Pennsylvania Institutional Review Board deemed this study exempt from review.
RESULTS
The sample comprised 57.0% (85/149) of IM and 54.4% (31/57) of GS residents (Table 1). Among respondents, perceived unnecessary inpatient laboratory test ordering was self‐reported by 88.2% of IM and 67.7% of GS residents. This behavior was reported to occur on a daily basis by 43.5% and 32.3% of responding IM and GS residents, respectively. Across both specialties, the most commonly reported factors contributing to these behaviors were learned practice habit/routine (90.5%), a lack of understanding of the costs associated with lab tests (86.2%), diagnostic uncertainty (82.8%), and fear of not having the lab result information when requested by an attending (75.9%). There were no significant differences in any of these contributing factors by specialty or PGY level. Among respondents who completed a free‐text response (IM: 76 of 85; GS: 21 of 31), the most commonly proposed interventions to address these issues were increasing cost transparency (IM 40.8%; GS 33.3%), improvements to faculty role modeling (IM 30.2%; GS 33.3%), and computerized reminders or decision support (IM 21.1%; GS 28.6%) (Table 2).
| Residents (n = 116)* | |
|---|---|
| |
| Reported he or she orders unnecessary routine labs, no. (%) | 96 (82.8) |
| Frequency of ordering unnecessary labs, no. (%) | |
| Daily | 47 (49.0) |
| 23 times/week | 44 (45.8) |
| 1 time/week or less | 5 (5.2) |
| Agreement with statement as factors contributing to ordering unnecessary labs, no. (%) | |
| Practice habit; I am trained to order repeating daily labs | 105 (90.5) |
| Lack of cost transparency of labs | 100 (86.2) |
| Discomfort with diagnostic uncertainty | 96 (82.8) |
| Concern that the attending will ask for the data and I will not have it | 88 (75.9) |
| Lack of role modeling of cost conscious care | 78 (67.2) |
| Lack of cost conscious culture at our institution | 76 (65.5) |
| Lack of experience | 72 (62.1) |
| Ease of ordering repeating labs in EHR | 60 (51.7) |
| Fear of litigation from missed diagnosis related to lab data | 44 (37.9) |
| Categories* | Representative Quotes | IM, n = 76, No. (%) | GS, n = 21, No. (%) |
|---|---|---|---|
| |||
| Cost transparency | Let us know the costs of what we order and train us to remember that a patient gets a bill and we are contributing to a possible bankruptcy or hardship. | 31 (40.8) | 7 (33.3) |
| Display the cost of labs when [we're] ordering them [in the EHR]. | |||
| Post the prices so that MDs understand how much everything costs. | |||
| Role modeling restrain | Train attendings to be more critical about necessity of labs and overordering. Make it part of rounding practice to decide on the labs truly needed for each patient the next day. | 23 (30.2) | 7 (33.3) |
| Attendings could review daily lab orders and briefly explain which they do not believe we need. This would allow residents to learn from their experience and their thought processes. | |||
| Encouragement and modeling of this practice from the faculty perhaps by laying out more clear expectations for which clinical situations warrant daily labs and which do not. | |||
| Computerized or decision support | When someone orders labs and the previous day's lab was normal or labs were stable for 2 days, an alert should pop up to reconsider. | 16 (21.1) | 6 (28.6) |
| Prevent us from being able to order repeating [or standing] labs. | |||
| Track how many times labs changed management, and restrict certain labslike LFTs/coags. | |||
| High‐value care educational curricula | Increase awareness of issue by having a noon conference about it or some other forum for residents to discuss the issue. | 12 (15.8) | 4 (19.0) |
| Establish guidelines for housestaff to learn/follow from start of residency. | |||
| Integrate cost conscious care into training program curricula. | |||
| System improvements | Make it easier to get labs later [in the day] | 6 (7.9) | 2 (9.5) |
| Improve timeliness of phlebotomy/laboratory systems. | |||
| More responsive phlebotomy. | |||
DISCUSSION
A significant portion of inpatient laboratory testing is unnecessary,[2] creating an opportunity to reduce utilization and associated costs. Our findings demonstrate that these behaviors occur at high levels among residents (IM 88.2%; GS 67.7%) at a large academic medical center. These findings also reveal that residents attribute this behavior to practice habit, lack of access to cost data, and perceived expectations for daily lab ordering by faculty. Interventions to change these behaviors will need to involve changes to the health system culture, increasing transparency of the costs associated with healthcare services, and shifting to a model of education that celebrates restraint.[11]
Our study adds to the emerging quest for delivering value in healthcare and provides several important insights for hospitalists and medical educators at academic centers. First, our findings reflect the significant role that the clinical learning environment plays in influencing practice behaviors among residents. Residency training is a critical time when physicians begin to form habits that imprint upon their future practice patterns,[5] and our residents are aware that their behavior to order what they perceive to be unnecessary laboratory tests is driven by habit. Studies[6, 7] have shown that residents may implicitly accept certain styles of practice as correct and are more likely to adopt those styles during the early years of their training. In our institution, for example, the process of ordering standing or daily morning labs using a repeated copy‐forward function in the electronic health record is a common, learned practice (a ritual) that is passed down from senior to junior residents year after year. This practice is common across both training specialties. There is a need to better understand, measure, and change the culture in the clinical learning environment to demonstrate practices and values that model high‐value care for residents. Multipronged interventions that address culture, oversight, and systems change[12] are necessary to facilitate effective physician stewardship of inpatient laboratory testing and attack a problem so deeply ingrained in habit.
Second, residents in our study believe that access to cost information will better equip them to reduce unnecessary lab ordering. Two recent systematic reviews[13, 14] have shown that having real‐time access to charges changes physician ordering and prescribing behavior. Increasing cost transparency may not only be an important intervention for hospitals to reduce overuse and control cost, but also better arm resident physicians with the information they need to make higher‐value recommendations for their patients and be stewards of healthcare resources.
Third, our study highlights that residents' unnecessary laboratory utilization is driven by perceived, unspoken expectations for such ordering by faculty. This reflects an important undercurrent in the medical education system that has historically emphasized and rewarded thoroughness while often penalizing restraint.[11] Hospitalists can play a major role in changing these behaviors by sharing their expectations regarding test ordering at the beginning of teaching rotations, including teaching points that discourage overutilization during rounds, and role modeling high‐value care in their own practice. Taken together and practiced routinely, these hospitalist behaviors could prevent poor habits from forming in our trainees and discourage overinvestigation. Hospitalists must be responsible to disseminate the practice of restraint to achieve more cost‐effective care. Purposeful faculty development efforts in the area of high‐value care are needed. Additionally, supporting physician leaders that serve as the institutional bridge between graduate medical education and the health system[15] could foster an environment conducive to coaching residents and faculty to reduce unnecessary practice variation.
This study is subject to several limitations. First, the survey was conducted at a single academic medical center, with a modest response rate, and thus our findings may not be generalizable to other settings or residents of different training programs. Second, we did not validate residents' perception of whether or not tests were, in fact, unnecessary. We also did not validate residents' self‐reporting of their own behavior, which may vary from actual behavior. Lack of validation at the level of the tests and at the level of the residents' behavior are two distinct but inter‐related limitations. Although self‐reported responses among residents are an important indicator of their practice, validating these data with objective measures, such as a measure of necessity of ordered lab tests as determined by an expert physician or group of experienced physicians or the number of inpatient labs ordered by residents, may add further insights. Ordering of perceived unnecessary tests may be even more common if there was under‐reporting of this behavior. Third, although we provided a definition within the survey, interpretation among survey respondents of the term unnecessary may vary, and this variation may contribute to our findings. However, we did provide a clear definition in the survey and we attempted to mitigate this with feedback from residents on our preliminary pilot.
In conclusion, this is one of the first qualitative evaluations to explore residents' perceptions on why they order unnecessary inpatient laboratory tests. Our findings offer a rich understanding of residents' beliefs about their own role in unnecessary lab ordering and explore possible solutions through the lens of the resident. Yet, it is unclear whether tests deemed unnecessary by residents would also be considered unnecessary by attending physicians or even patients. Future efforts are needed to better define which inpatient tests are unnecessary from multiple perspectives including clinicians and patients.
Acknowledgements
The authors thank Patrick J. Brennan, MD, Jeffery S. Berns, MD, Lisa M. Bellini, MD, Jon B. Morris, MD, and Irving Nachamkin, DrPH, MPH, all from the Hospital of the University of Pennsylvania, for supporting this work. They received no compensation.
Disclosures: This work was presented in part at the AAMC Integrating Quality Meeting, June 11, 2015, Chicago, Illinois; and the Alliance for Academic Internal Medicine Fall Meeting, October 9, 2015, Atlanta, Georgia. The authors report no conflicts of interest.
- , , , . The impact of residents, interns, and attendings on inpatient laboratory ordering patterns: a report from one university's hospitalist service. Acad Med. 2011;86(1):139–145.
- , , , , . The landscape of inappropriate laboratory testing: a 15‐year meta‐analysis. PLoS One. 2013;8(11):e78962.
- , , , et al. Diagnostic blood loss from phlebotomy and hospital‐acquired anemia during acute myocardial infarction. Arch Intern Med. 2011;171(18):1646–1653.
- , , , et al. Choosing wisely in adult hospital medicine: five opportunities for improved healthcare value. J Hosp Med. 2013;8(9):486–492.
- . Charting the route to high‐value care the role of medical education. JAMA. 2016;314(22):2359–2361.
- , , , , . Spending patterns in region of residency training and subsequent expenditures for care provided by practicing physicians for Medicare beneficiaries. JAMA. 2014;312(22):2385–2393.
- , , , . The association between residency training and internists' ability to practice conservatively. JAMA Intern Med. 2014;174(10):1640–1648.
- , , , , . Effect of attending practice style on generic medication prescribing by residents in the clinic setting: an observational study. J Gen Intern Med. 2015;30(9):1286–1293.
- , , , . Role‐modeling cost‐conscious care—a national evaluation of perceptions of faculty at teaching hospitals in the United States. J Gen Intern Med. 2015;30(9):1294–1298.
- , . The discovery of grounded theory. Int J Qual Methods. 1967;5:1–10.
- , . A new model for medical education: celebrating restraint. JAMA. 2012;308(13):1329–1330.
- , , . A framework for the frontline: how hospitalists can improve healthcare value. J Hosp Med. 2016;11(4):297–302.
- , , , . The effect of charge display on cost of care and physician practice behaviors: a systematic review. J Gen Intern Med. 2015;30(6):835–842.
- , , , . Impact of price display on provider ordering: a systematic review. J Hosp Med. 2016;11(1):65–76.
- , . Merging the health system and education silos to better educate future physicians. JAMA. 2015;314(22):2349–2350.
- , , , . The impact of residents, interns, and attendings on inpatient laboratory ordering patterns: a report from one university's hospitalist service. Acad Med. 2011;86(1):139–145.
- , , , , . The landscape of inappropriate laboratory testing: a 15‐year meta‐analysis. PLoS One. 2013;8(11):e78962.
- , , , et al. Diagnostic blood loss from phlebotomy and hospital‐acquired anemia during acute myocardial infarction. Arch Intern Med. 2011;171(18):1646–1653.
- , , , et al. Choosing wisely in adult hospital medicine: five opportunities for improved healthcare value. J Hosp Med. 2013;8(9):486–492.
- . Charting the route to high‐value care the role of medical education. JAMA. 2016;314(22):2359–2361.
- , , , , . Spending patterns in region of residency training and subsequent expenditures for care provided by practicing physicians for Medicare beneficiaries. JAMA. 2014;312(22):2385–2393.
- , , , . The association between residency training and internists' ability to practice conservatively. JAMA Intern Med. 2014;174(10):1640–1648.
- , , , , . Effect of attending practice style on generic medication prescribing by residents in the clinic setting: an observational study. J Gen Intern Med. 2015;30(9):1286–1293.
- , , , . Role‐modeling cost‐conscious care—a national evaluation of perceptions of faculty at teaching hospitals in the United States. J Gen Intern Med. 2015;30(9):1294–1298.
- , . The discovery of grounded theory. Int J Qual Methods. 1967;5:1–10.
- , . A new model for medical education: celebrating restraint. JAMA. 2012;308(13):1329–1330.
- , , . A framework for the frontline: how hospitalists can improve healthcare value. J Hosp Med. 2016;11(4):297–302.
- , , , . The effect of charge display on cost of care and physician practice behaviors: a systematic review. J Gen Intern Med. 2015;30(6):835–842.
- , , , . Impact of price display on provider ordering: a systematic review. J Hosp Med. 2016;11(1):65–76.
- , . Merging the health system and education silos to better educate future physicians. JAMA. 2015;314(22):2349–2350.
Does this patient need ultrasonography of the leg to evaluate for deep vein thrombosis?
A 38-year-old woman presents to the emergency department after experiencing several days of swelling and mild discomfort in her left calf. She denies chest pain or shortness of breath. She does not recall antecedent trauma, is a nonsmoker, is healthy, and takes no medications apart from a multivitamin. She has not undergone any surgical procedure, has not been hospitalized recently, and has no history of venous thromboembolic disease. She says she started an aerobics program 1 week ago.
On examination, her left lower leg is mildly swollen, but the difference in calf circumference between the right and left legs is less than 1 cm. There is no erythema, no pitting edema, and only mild and rather diffuse tenderness of the calf. A urine pregnancy test is negative and her D-dimer level is 350 ng/mL (reference range < 500 ng/mL). Does she require ultrasonography of the left leg to evaluate for deep vein thrombosis (DVT)?
This patient does not need confirmatory ultrasonography, as her normal D-dimer level of 350 ng/mL is enough to rule out DVT. Her low probability of having DVT is further supported by her Wells score (Table 1), a tool that can help rule out DVT and reduce the need for further testing. DVT is unlikely if a patient’s Wells score is less than 2, and this patient’s score is –1. She receives 1 point for swelling of her left lower leg, but injury from her recent aerobic exercise is at least as likely as DVT to account for her symptoms (–2 points).
GUIDELINES AND CHOOSING WISELY
Compression ultrasonography is the study most commonly used to evaluate for DVT. The diagnosis is made if either the femoral or popliteal vein is noncompressible.1 In a patient with no history of DVT, the sensitivity of compression ultrasonography is 94%, and its specificity is 98%.
Several guidelines recommend using a clinical decision rule to establish the probability of venous thromboembolic disease before any additional diagnostic testing such as D-dimer measurement or ultrasonography.2–4 A number of clinical decision rules exist for DVT, but the Wells score is the most studied and validated.1 It incorporates the patient’s risk factors, symptoms, and signs to categorize the probability of DVT as low, moderate, or high and has been further modified to classify the risk as either likely or unlikely (Table 1).5
Guidelines from the American College of Chest Physicians (2012), Scottish Intercollegiate Guidelines Network (2010), and American Academy of Family Physicians and American College of Physicians (2007) recommend against performing imaging if a high-sensitivity D-dimer test is negative in a patient in whom the pretest probability of DVT is unlikely.2–4 Enzyme-linked immunofluorescence assays, microplate enzyme-linked immunosorbent assays, and latex quantitative assays are considered high-sensitivity D-dimer tests, having 96%, 94%, and 93% sensitivity, respectively, in ruling out DVT.1 Other D-dimer tests have lower sensitivity and cannot comfortably rule out DVT even if the results are negative.
Since D-dimer measurement is a sensitive but not specific test, it should be used only to rule out DVT—not to rule it in. Moreover, compression ultrasonography may be indicated to rule out other causes of the patient’s symptoms.
The guidelines caution against D-dimer testing if the patient has a comorbid condition that can by itself raise or lower the D-dimer level, leading one to falsely conclude the patient has or does not have DVT (Table 2).1–4 In these instances, the pretest probability of DVT may be higher than calculated by a clinical prediction rule, and compression ultrasonography may be an appropriate initial test.4 Compression ultrasonography is also recommended as a confirmatory test in low-risk patients who have a positive D-dimer test or as an initial test in patients at higher risk for DVT.2–4
If a patient has a low pretest probability of DVT as defined by the Wells score and a normal high-sensitivity D-dimer measurement, then ordering imaging studies is a questionable practice according to statements by the American College of Physicians, American College of Emergency Physicians, European Society of Cardiology, American Academy of Family Physicians, and Scottish Intercollegiate Guidelines Network.
HARMS OF ULTRASONOGRAPHY
Although ultrasonography is generally well tolerated, it may be unnecessary. Combining a prediction rule (to assess the probability) with D-dimer testing (to rule out DVT) can significantly reduce the use of ultrasonography and the associated cost.
Wells et al5 calculated that clinicians could cut back on ultrasonographic testing by 39% by not doing it in those who had a low pretest probability and a negative D-dimer test result.5 In that patient population, fewer than 1% of patients were later found to have DVT.
Ordering compression ultrasonography as additional testing may lead to a false-positive result and to additional unnecessary testing and treatments that would inconvenience the patient, increase the risk of serious complications such as bleeding, and incur increased costs. Cost considerations should include not only the cost of the test and its interpretation, but also the workup and treatment of false-positive results, patient time missed from work while being tested, and potential associated costs for patients who need to be evaluated in the emergency department to obtain same-day testing.
THE CLINICAL BOTTOM LINE
Our patient’s Wells score indicates that DVT is unlikely. A negative D-dimer test is sufficient to rule out DVT, and further testing is unnecessary.
- Huisman MV, Klok FA. Diagnostic management of acute deep vein thrombosis and pulmonary embolism. J Thromb Haemost 2013; 11:412–422.
- Bates SM, Jaeschke R, Stevens EM, et al. Antithrombotic therapy and prevention of thrombosis, 9th edition: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines. Chest 2012; 141(2 suppl):e351S–e418S.
- Scottish Intercollegiate Guidelines Network (SIGN). Prevention and management of venous thromboembolism. A national clinical guideline. Edinburgh (Scotland): Scottish Intercollegiate Guidelines Network (SIGN); 2010: http://sign.ac.uk/guidelines/fulltext/122/index.html. Accessed February 6, 2015.
- Qaseem A, Snow V, Barry P, et al. Current diagnosis of venous thromboembolism in primary care: a clinical practice guideline from the American Academy of Family Physicians and the American College of Physicians. Ann Intern Med 2007; 146:454–458.
- Wells PS, Anderson DR, Rodger M, et al. Evaluation of D-dimer in the diagnosis of suspected deep-vein thrombosis. N Engl J Med 2003; 349:1227–1235.
A 38-year-old woman presents to the emergency department after experiencing several days of swelling and mild discomfort in her left calf. She denies chest pain or shortness of breath. She does not recall antecedent trauma, is a nonsmoker, is healthy, and takes no medications apart from a multivitamin. She has not undergone any surgical procedure, has not been hospitalized recently, and has no history of venous thromboembolic disease. She says she started an aerobics program 1 week ago.
On examination, her left lower leg is mildly swollen, but the difference in calf circumference between the right and left legs is less than 1 cm. There is no erythema, no pitting edema, and only mild and rather diffuse tenderness of the calf. A urine pregnancy test is negative and her D-dimer level is 350 ng/mL (reference range < 500 ng/mL). Does she require ultrasonography of the left leg to evaluate for deep vein thrombosis (DVT)?
This patient does not need confirmatory ultrasonography, as her normal D-dimer level of 350 ng/mL is enough to rule out DVT. Her low probability of having DVT is further supported by her Wells score (Table 1), a tool that can help rule out DVT and reduce the need for further testing. DVT is unlikely if a patient’s Wells score is less than 2, and this patient’s score is –1. She receives 1 point for swelling of her left lower leg, but injury from her recent aerobic exercise is at least as likely as DVT to account for her symptoms (–2 points).
GUIDELINES AND CHOOSING WISELY
Compression ultrasonography is the study most commonly used to evaluate for DVT. The diagnosis is made if either the femoral or popliteal vein is noncompressible.1 In a patient with no history of DVT, the sensitivity of compression ultrasonography is 94%, and its specificity is 98%.
Several guidelines recommend using a clinical decision rule to establish the probability of venous thromboembolic disease before any additional diagnostic testing such as D-dimer measurement or ultrasonography.2–4 A number of clinical decision rules exist for DVT, but the Wells score is the most studied and validated.1 It incorporates the patient’s risk factors, symptoms, and signs to categorize the probability of DVT as low, moderate, or high and has been further modified to classify the risk as either likely or unlikely (Table 1).5
Guidelines from the American College of Chest Physicians (2012), Scottish Intercollegiate Guidelines Network (2010), and American Academy of Family Physicians and American College of Physicians (2007) recommend against performing imaging if a high-sensitivity D-dimer test is negative in a patient in whom the pretest probability of DVT is unlikely.2–4 Enzyme-linked immunofluorescence assays, microplate enzyme-linked immunosorbent assays, and latex quantitative assays are considered high-sensitivity D-dimer tests, having 96%, 94%, and 93% sensitivity, respectively, in ruling out DVT.1 Other D-dimer tests have lower sensitivity and cannot comfortably rule out DVT even if the results are negative.
Since D-dimer measurement is a sensitive but not specific test, it should be used only to rule out DVT—not to rule it in. Moreover, compression ultrasonography may be indicated to rule out other causes of the patient’s symptoms.
The guidelines caution against D-dimer testing if the patient has a comorbid condition that can by itself raise or lower the D-dimer level, leading one to falsely conclude the patient has or does not have DVT (Table 2).1–4 In these instances, the pretest probability of DVT may be higher than calculated by a clinical prediction rule, and compression ultrasonography may be an appropriate initial test.4 Compression ultrasonography is also recommended as a confirmatory test in low-risk patients who have a positive D-dimer test or as an initial test in patients at higher risk for DVT.2–4
If a patient has a low pretest probability of DVT as defined by the Wells score and a normal high-sensitivity D-dimer measurement, then ordering imaging studies is a questionable practice according to statements by the American College of Physicians, American College of Emergency Physicians, European Society of Cardiology, American Academy of Family Physicians, and Scottish Intercollegiate Guidelines Network.
HARMS OF ULTRASONOGRAPHY
Although ultrasonography is generally well tolerated, it may be unnecessary. Combining a prediction rule (to assess the probability) with D-dimer testing (to rule out DVT) can significantly reduce the use of ultrasonography and the associated cost.
Wells et al5 calculated that clinicians could cut back on ultrasonographic testing by 39% by not doing it in those who had a low pretest probability and a negative D-dimer test result.5 In that patient population, fewer than 1% of patients were later found to have DVT.
Ordering compression ultrasonography as additional testing may lead to a false-positive result and to additional unnecessary testing and treatments that would inconvenience the patient, increase the risk of serious complications such as bleeding, and incur increased costs. Cost considerations should include not only the cost of the test and its interpretation, but also the workup and treatment of false-positive results, patient time missed from work while being tested, and potential associated costs for patients who need to be evaluated in the emergency department to obtain same-day testing.
THE CLINICAL BOTTOM LINE
Our patient’s Wells score indicates that DVT is unlikely. A negative D-dimer test is sufficient to rule out DVT, and further testing is unnecessary.
A 38-year-old woman presents to the emergency department after experiencing several days of swelling and mild discomfort in her left calf. She denies chest pain or shortness of breath. She does not recall antecedent trauma, is a nonsmoker, is healthy, and takes no medications apart from a multivitamin. She has not undergone any surgical procedure, has not been hospitalized recently, and has no history of venous thromboembolic disease. She says she started an aerobics program 1 week ago.
On examination, her left lower leg is mildly swollen, but the difference in calf circumference between the right and left legs is less than 1 cm. There is no erythema, no pitting edema, and only mild and rather diffuse tenderness of the calf. A urine pregnancy test is negative and her D-dimer level is 350 ng/mL (reference range < 500 ng/mL). Does she require ultrasonography of the left leg to evaluate for deep vein thrombosis (DVT)?
This patient does not need confirmatory ultrasonography, as her normal D-dimer level of 350 ng/mL is enough to rule out DVT. Her low probability of having DVT is further supported by her Wells score (Table 1), a tool that can help rule out DVT and reduce the need for further testing. DVT is unlikely if a patient’s Wells score is less than 2, and this patient’s score is –1. She receives 1 point for swelling of her left lower leg, but injury from her recent aerobic exercise is at least as likely as DVT to account for her symptoms (–2 points).
GUIDELINES AND CHOOSING WISELY
Compression ultrasonography is the study most commonly used to evaluate for DVT. The diagnosis is made if either the femoral or popliteal vein is noncompressible.1 In a patient with no history of DVT, the sensitivity of compression ultrasonography is 94%, and its specificity is 98%.
Several guidelines recommend using a clinical decision rule to establish the probability of venous thromboembolic disease before any additional diagnostic testing such as D-dimer measurement or ultrasonography.2–4 A number of clinical decision rules exist for DVT, but the Wells score is the most studied and validated.1 It incorporates the patient’s risk factors, symptoms, and signs to categorize the probability of DVT as low, moderate, or high and has been further modified to classify the risk as either likely or unlikely (Table 1).5
Guidelines from the American College of Chest Physicians (2012), Scottish Intercollegiate Guidelines Network (2010), and American Academy of Family Physicians and American College of Physicians (2007) recommend against performing imaging if a high-sensitivity D-dimer test is negative in a patient in whom the pretest probability of DVT is unlikely.2–4 Enzyme-linked immunofluorescence assays, microplate enzyme-linked immunosorbent assays, and latex quantitative assays are considered high-sensitivity D-dimer tests, having 96%, 94%, and 93% sensitivity, respectively, in ruling out DVT.1 Other D-dimer tests have lower sensitivity and cannot comfortably rule out DVT even if the results are negative.
Since D-dimer measurement is a sensitive but not specific test, it should be used only to rule out DVT—not to rule it in. Moreover, compression ultrasonography may be indicated to rule out other causes of the patient’s symptoms.
The guidelines caution against D-dimer testing if the patient has a comorbid condition that can by itself raise or lower the D-dimer level, leading one to falsely conclude the patient has or does not have DVT (Table 2).1–4 In these instances, the pretest probability of DVT may be higher than calculated by a clinical prediction rule, and compression ultrasonography may be an appropriate initial test.4 Compression ultrasonography is also recommended as a confirmatory test in low-risk patients who have a positive D-dimer test or as an initial test in patients at higher risk for DVT.2–4
If a patient has a low pretest probability of DVT as defined by the Wells score and a normal high-sensitivity D-dimer measurement, then ordering imaging studies is a questionable practice according to statements by the American College of Physicians, American College of Emergency Physicians, European Society of Cardiology, American Academy of Family Physicians, and Scottish Intercollegiate Guidelines Network.
HARMS OF ULTRASONOGRAPHY
Although ultrasonography is generally well tolerated, it may be unnecessary. Combining a prediction rule (to assess the probability) with D-dimer testing (to rule out DVT) can significantly reduce the use of ultrasonography and the associated cost.
Wells et al5 calculated that clinicians could cut back on ultrasonographic testing by 39% by not doing it in those who had a low pretest probability and a negative D-dimer test result.5 In that patient population, fewer than 1% of patients were later found to have DVT.
Ordering compression ultrasonography as additional testing may lead to a false-positive result and to additional unnecessary testing and treatments that would inconvenience the patient, increase the risk of serious complications such as bleeding, and incur increased costs. Cost considerations should include not only the cost of the test and its interpretation, but also the workup and treatment of false-positive results, patient time missed from work while being tested, and potential associated costs for patients who need to be evaluated in the emergency department to obtain same-day testing.
THE CLINICAL BOTTOM LINE
Our patient’s Wells score indicates that DVT is unlikely. A negative D-dimer test is sufficient to rule out DVT, and further testing is unnecessary.
- Huisman MV, Klok FA. Diagnostic management of acute deep vein thrombosis and pulmonary embolism. J Thromb Haemost 2013; 11:412–422.
- Bates SM, Jaeschke R, Stevens EM, et al. Antithrombotic therapy and prevention of thrombosis, 9th edition: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines. Chest 2012; 141(2 suppl):e351S–e418S.
- Scottish Intercollegiate Guidelines Network (SIGN). Prevention and management of venous thromboembolism. A national clinical guideline. Edinburgh (Scotland): Scottish Intercollegiate Guidelines Network (SIGN); 2010: http://sign.ac.uk/guidelines/fulltext/122/index.html. Accessed February 6, 2015.
- Qaseem A, Snow V, Barry P, et al. Current diagnosis of venous thromboembolism in primary care: a clinical practice guideline from the American Academy of Family Physicians and the American College of Physicians. Ann Intern Med 2007; 146:454–458.
- Wells PS, Anderson DR, Rodger M, et al. Evaluation of D-dimer in the diagnosis of suspected deep-vein thrombosis. N Engl J Med 2003; 349:1227–1235.
- Huisman MV, Klok FA. Diagnostic management of acute deep vein thrombosis and pulmonary embolism. J Thromb Haemost 2013; 11:412–422.
- Bates SM, Jaeschke R, Stevens EM, et al. Antithrombotic therapy and prevention of thrombosis, 9th edition: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines. Chest 2012; 141(2 suppl):e351S–e418S.
- Scottish Intercollegiate Guidelines Network (SIGN). Prevention and management of venous thromboembolism. A national clinical guideline. Edinburgh (Scotland): Scottish Intercollegiate Guidelines Network (SIGN); 2010: http://sign.ac.uk/guidelines/fulltext/122/index.html. Accessed February 6, 2015.
- Qaseem A, Snow V, Barry P, et al. Current diagnosis of venous thromboembolism in primary care: a clinical practice guideline from the American Academy of Family Physicians and the American College of Physicians. Ann Intern Med 2007; 146:454–458.
- Wells PS, Anderson DR, Rodger M, et al. Evaluation of D-dimer in the diagnosis of suspected deep-vein thrombosis. N Engl J Med 2003; 349:1227–1235.
