BACKGROUND Fingerstick blood samples are used to estimate donor venous hemoglobin (Hb). STUDY DESIGN AND METHODS Fingerstick Hb or hematocrit (Hct) was determined routinely for 2425 selected donors at six blood centers, along with venous Hb. Using sex and measures of iron status including absent iron stores (AIS; ferritin < 12 ng/mL), linear regression models were developed to predict venous Hb from fingerstick. RESULTS Across all subjects, fingerstick Hb was higher than venous Hb in the higher part of the clinical range, but lower in the lower part of the range. The relationship varied by sex and iron status. Across centers, a female donor had on average a venous Hb result 0.5 to 0.8 g/dL lower than a male donor with the same fingerstick Hb and iron status. Similarly, a donor with AIS had on average a venous Hb result 0.3 to 1.1 g/dL lower than an iron-replete donor with the same fingerstick value and sex. An iron-replete male donor with a fingerstick result at the cutoff (Hb 12.5 g/dL) had an acceptable expected venous Hb (12.8 to 13.8 g/dL). A female donor with AIS with a fingerstick result at the cutoff had an expected venous Hb below 12.5 g/dL (11.7 to 12.4 g/dL). Of females with AIS, 40.2% donated blood when their venous Hb was less than 12.5 g/dL. CONCLUSIONS Fingerstick is considered a useful estimator of venous Hb. However, in some donor groups, particularly female donors with AIS, fingerstick overestimates venous Hb at the donation cutoff. This significant limitation should be considered in setting donor fingerstick Hb or Hct requirements.

BACKGROUND A minimum male hemoglobin (Hb) of 13.0 g/dL will become an FDA requirement in May 2016. In addition, extending whole blood (WB) interdonation intervals (IDIs) beyond 8 weeks has been considered in order to reduce iron depletion in repeat blood donors. This study estimates the impact these changes might have on blood availability and donor iron status. STUDY DESIGN AND METHODS Six blood centers participating in REDS-II collected information on all donation visits from 2006–09. Simulations were developed from these data using a multi-stage approach that first sought to adequately reproduce the patterns of donor return, Hb and ferritin levels, and outcomes of a donor’s visit (successful single or double RBC donation, deferral for low Hb) observed in REDS-II datasets. Modified simulations were used to predict the potential impact on the blood supply and donor iron status under different Hb cutoff and IDI qualification criteria. RESULTS More than 10% of WB donations might require replacement under many simulated scenarios. Longer IDIs would reduce the proportion of donors with iron depletion, but 80% of these donors may remain iron-depleted if minimal IDIs increased to 12 or 16 weeks. CONCLUSION Higher Hb cutoffs and longer IDIs are predicted to have a potentially large impact on collections but only a modest impact on donor iron depletion. Efforts to address iron depletion should be targeted to at-risk donors, such as iron supplementation programs for frequent donors, and policy makers should try to avoid broadly restrictive donation requirements that could substantially reduce blood availability.

Summary Frequent blood donors become iron deficient. HFE mutations are present in over 30% of donors. A 24-month study of 888 first time/reactivated donors and 1537 frequent donors measured haemoglobin and iron status to assess how HFE mutations impact the development of iron deficiency erythropoiesis. Donors with two HFE mutations had increased baseline haemoglobin and iron stores as did those with one mutation, albeit to a lesser extent. Over multiple donations haemoglobin and iron status of donors with HFE mutations paralleled those lacking mutations. The prevalence of HFE mutations was not increased in higher intensity donors. Thus, in general, HFE mutations do not temper donation-induced changes in haemoglobin and iron status. However, in Black donors there was an increase of H63D carriers at baseline, from 3.7% in first time/reactivated donors to 15.8% in frequent donors, suggesting that the relative effects of HFE mutations on iron absorption may vary between racial/ethnic groups. In secondary analyses, venous haemoglobin decreased more slowly in donors with ferritin ≥ 12 μg/l; and haemoglobin recovery time was shorter in donors with reticulocyte haemoglobin (CHr) ≥ 32.6 pg, indicating that these biochemical measures are better indicators of a donor’s response to phlebotomy than their HFE mutation status.

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Aim The objective of this study was to determine whether changes in carboxyhaemoglobin (COHb) saturation following carbon monoxide (CO) rebreathing can be accurately detected by Pulse CO-Oximetry in order to determine blood volume. Methods Noninvasive measurements of carboxyhaemoglobin saturation (SpCO) were continuously monitored by Pulse CO-Oximetry before, during and following 2 minutes of CO rebreathing. Reproducibility and accuracy of noninvasive blood volume measurements were determined in 16 healthy non-smoking individuals (15 males, age: 28 ± 2 years, body mass index: 25.4 ± 0.6 kg/m2) through comparison with blood volume measurements calculated from invasive measurements of COHb saturation. Results The coefficient of variation for noninvasive blood volume measurements performed on separate days was 15.1% which decreases to 9.1% when measurements were performed on the same day. Changes in COHb saturation and SpCO following CO rebreathing were strongly correlated (r=0.90, p<0.01), resulting in a significant correlation between invasive and noninvasive blood volume measurements (r=0.83, p=0.02). Conclusion Changes in SpCO following CO rebreathing can be accurately detected by Pulse CO-Oximetry, which could potentially provide a simplified, convenient and reproducible method to rapidly determine blood volume in healthy individuals.