and approximately 15% of males and one-third of females may be iron depleted 1 year after a red blood cell donation, according to a study published online in Pediatrics.
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“Our findings ... support the strong encouragement of postdonation low-dose iron supplements, at least in teenagers with already low or borderline iron stores,” said Ralph R. Vassallo, MD and colleagues. An increased interdonation interval for teenage blood donors may need to be considered. Dr. Vassallo is executive vice president and chief medical and scientific officer at Vitalant, a community blood service provider based in Scottsdale, Ariz., that collects approximately 14% of the U.S. blood supply.
Data from a safety initiative
Iron deficiency may erode exercise performance, lead to pica, and have subtle cognitive effects. Iron that is lost during blood donation may be difficult to replace on an average Western diet, the researchers said. Knowledge of the time course of iron recovery is limited, and recent studies have found high rates of mild iron depletion or absent stores in teenage blood donors.
As a safety initiative, Vitalant began serum ferritin testing of predonation specimens from successful donations by 16- to 18-year-old donors to identify iron deficiency. The researchers defined inadequate iron stores as ferritin values less than 20 ng/mL in female donors and less than 30 ng/mL in male donors.
While whole-blood donors generally were deferred from red blood cell donation for 56 days and double red blood cell donors were deferred from any donation for 112 days, teenagers found to have low ferritin were deferred longer: 12 months for females and 6 months for males. Teenagers with low ferritin also were counseled by letter to take low-dose (18-28 mg) iron for 60 days.
Vitalant began conducting serum ferritin tests on Dec. 19, 2016, and the researchers analyzed data that were available through Dec. 31, 2018. The study included data from teen donors aged 16-18 years from 24 states.
In all, 125,384 teenagers donated whole blood or double red blood cells at least once, and 39% of females and 12% of males had a low-index ferritin value. The researchers focused on 30,806 teenagers (24.6%) who returned and successfully donated again within 25 months. In this cohort, 11% of female donors and 10% of male donors had a low-index ferritin value.
Twelve months after the first whole-blood donation, 80%-90% of males and 60%-70% of females had adequate iron stores. These proportions were about 10% lower for double red blood cell donors.
Among whole-blood donors, the percentage of donors with adequate iron stores at a follow-up donation “is highly dependent on index ferritin,” Dr. Vassallo and colleagues reported. For 90% of donors to have adequate iron stores within 3-9 months of index donation, index ferritin values had to be at least 47 ng/mL for males and 53 ng/mL for females, according to their analysis.
“At least 12 months are required for a sizeable proportion to reach next-donation ferritin values indicative of adequate iron stores,” the researchers said. “However, donor sex, donation type, first-time versus repeat status, and ferritin level at index were significant determinants of iron stores at the follow-up donation.”
“The enthusiasm of altruistic, highly motivated young donors makes large high school and college blood drives efficient and productive,” but these donors may be at increased risk for donation-related iron depletion, they said.
The estimated intervals needed to replenish iron stores represent best-case scenarios, the authors noted. The cohort did not include individuals deferred for low hemoglobin, likely due to iron deficiency, and these donors probably require more time to replenish iron stores.
The data suggest that health care providers should consider blood donation as a possible cause of low hemoglobin, Dr. Vassallo and colleagues said. Before prescribing higher doses of iron, however, physicians should assess a patient’s risk for other causes of iron deficiency such as gastrointestinal blood loss or celiac disease.