Is high hemoglobin a hindrance factor for blood donation? A pilot observational study from the coastal region of India

Background: Blood donors with high Hb are often deferred for the presumed risk of polycythemia vera (PV). However, adequate data to substantiate or refute this hypothesis is lacking. Methodology: We conducted an observational study on blood donors found to have high hemoglobin (Hb ≥ 18 g/dL) during the pre-donation screening process using a portable hemoglobinometer at our blood center for four months. We adopted a cost effective methodology wherein a questionnaire was used to elicit the secondary causative factors of high hemoglobin and a complete blood count test to observe the blood cell parameters and JAK2V617F mutation test was performed in a subset of donors lacking secondary erythrocytosis (SE) history. Results: Of the total 7076 donors enrolled, 112 male donors (1.58%) had high hemoglobin. The majority (70.4%) were repeat donors with mean age of 31.4 years. About 61% of the donors had attributable factors for SE like smoking, occupational exposure to carbon monoxide. The mean hemoglobin value of capillary and venous hemoglobin demonstrated a statistically significant difference (P < 0.05) where 2.7% of donors had venous Hb < 18 g/dL. The hematological profile of all the donors showed increased RBC but normal platelet and WBC count. Of 24 donors included for the JAK2V617F test, none had a positive report. Conclusion: This study suggests high hemoglobin in blood donors is less likely due to PV. Hence, re-considering their deferral may help alleviate donor anxiety and allow donor return. However, multi-centric studies are required to develop consensus statements on PV risk status and blood donation eligibility.