Laboratory variables for assessing iron deficiency in REDS-II Iron Status Evaluation (RISE) blood donors.

BACKGROUND: Iron deficiency is common in regular blood donors. We evaluated the diagnostic sensitivity and specificity of red blood cell (RBC) hematology analyzer indices to assess iron status as a part of donor management. STUDY DESIGN AND METHODS: A total of 1659 male and female donors from the Retrovirus Epidemiology Donor Study-II (REDS-II) Donor Iron Status Evaluation (RISE) study who were either first-time/reactivated (FT/RA; no donations for 2 years) or frequent donors were recruited into a longitudinal study of regular donation of RBCs. Of these, 1002 donors returned 15 to 24 months later for a final assessment. Absent iron stores (AIS) was defined as plasma ferritin level of less than 12 µg/L. Logarithm of the ratio of soluble transferrin receptor to ferritin of at least 2.07 (≥97.5% in FT/RA males) was used to define iron-deficient erythropoiesis (IDE). Receiver operating characteristics analysis was performed to assess selected RBC indices (e.g., percentage of hypochromic mature RBCs, proportion of hypochromic mature RBCs [HYPOm], and hemoglobin [Hb] content of reticulocytes [CHr]) in identifying AIS and IDE. RESULTS: HYPOm and CHr detected IDE with comparable sensitivity, 72% versus 69%, but differed in specificity: HYPOm 68% and CHr 53%. For detecting AIS, sensitivity was improved to 85% for HYPOm and 81% for CHr but specificity was reduced for both. Venous Hb had high specificity but poor sensitivity for IDE and AIS. A plasma ferritin level of less than 26.7 µg/L was a good surrogate for assessing IDE. CONCLUSION: RBC indices correlate with AIS and IDE and are more informative than Hb measurement, but lack sufficient sensitivity and specificity to be used as diagnostic tools in blood donors at risk for iron deficiency.

Iron deficiency in blood donors: the REDS-II Donor Iron Status Evaluation (RISE) study.

BACKGROUND: Blood donors are at risk of iron deficiency. We evaluated the effects of blood donation intensity on iron and hemoglobin (Hb) in a prospective study. STUDY DESIGN AND METHODS: Four cohorts of frequent and first-time or reactivated (FT/RA) blood donors (no donation in 2 years), female and male, totaling 2425, were characterized and followed as they donated blood frequently. At enrollment and the final visit, ferritin, soluble transferrin receptor (sTfR), and Hb were determined. Models to predict iron deficiency and Hb deferral were developed. Iron depletion was defined at two levels: iron deficiency erythropoiesis (IDE) [log(sTfR/ferritin) ≥ 2.07] and absent iron stores (AIS; ferritin < 12 ng/mL). RESULTS: Among returning female FT and RA donors, 20 and 51% had AIS and IDE at their final visit, respectively; corresponding proportions for males were 8 and 20%. Among female frequent donors who returned, 27 and 62% had AIS and IDE, respectively, while corresponding proportions for males were 18 and 47%. Predictors of IDE and/or AIS included a higher frequency of blood donation in the past 2 years, a shorter interdonation interval, and being female and young; conversely, taking iron supplements reduced the risk of iron depletion. Predictors of Hb deferral included female sex, black race, and a shorter interdonation interval. CONCLUSIONS: There is a high prevalence of iron depletion in frequent blood donors. Increasing the interdonation interval would reduce the prevalence of iron depletion and Hb deferral. Alternatively, replacement with iron supplements may allow frequent donation without the adverse outcome of iron depletion.

Iron deficiency in blood donors: analysis of enrollment data from the REDS-II Donor Iron Status Evaluation (RISE) study.

BACKGROUND: Regular blood donors are at risk of iron deficiency, but characteristics that predispose to this condition are poorly defined. STUDY DESIGN AND METHODS: A total of 2425 red blood cell donors, either first-time (FT) or reactivated donors (no donations for 2 years) or frequent donors, were recruited for follow-up. At enrollment, ferritin, soluble transferrin receptor (sTfR), and hemoglobin were determined. Donor variables included demographics, smoking, dietary intake, use of iron supplements, and menstrual and/or pregnancy history. Models to predict two measures of iron deficiency were developed: Absent iron stores (AIS) were indicated by a ferritin level of less than 12 ng/mL and iron-deficient erythropoiesis (IDE) by a log(sTfR/ferritin) value of 2.07 or greater. RESULTS: A total of 15.0% of donors had AIS and 41.7% IDE. In frequent donors, 16.4 and 48.7% of males had AIS and IDE, respectively, with corresponding proportions of 27.1 and 66.1% for females. Donation intensity was most closely associated with AIS and/or IDE (odds ratios from 5.3 to 52.2 for different donation intensity compared to FT donors). Being female, younger, and/or menstruating also increased the likelihood of having AIS and/or IDE, as did having a lower weight. Marginally significant variables for AIS and/or IDE were being a nonsmoker, previous pregnancy, and not taking iron supplements. Dietary variables were in general unrelated to AIS and/or IDE, as was race and/or ethnicity. CONCLUSION: A large proportion of both female and male frequent blood donors have iron depletion. Donation intensity, sex and/or menstrual status, weight, and age are important independent predictors of AIS and/or IDE. Reducing the frequency of blood donation is likely to reduce the prevalence of iron deficiency among blood donors, as might implementing routine iron supplementation.