Abstract
OBJECTIVES: To systematically review evidence on the prevalence of the JAK2V617F (JAK2) mutation and polycythemia vera (PV) among all blood donors, focusing on those with elevated hematocrit. Although blood donors are generally healthy, considering a preclinical stage of myeloproliferative neoplasm, especially in those with polycythemia, is crucial. Evidence on managing these donors is limited. METHODS: We performed a literature search using EMBASE and MEDLINE from inception until August 2023, including studies on the prevalence of JAK2 mutation or PV among blood donors. Eligible studies examined blood donors in hospital or community settings, had a sample size of at least 20 donors, and reported the prevalence of the JAK2 mutation or PV. We assessed bias, extracted data, and used a random effects model meta-analysis to estimate pooled prevalence and 95% confidence intervals. Subgroup analysis differentiated donors with normal hematocrit from those with polycythemia. Heterogeneity was assessed using I2 statistics. RESULTS: Our review included eleven studies in total. Of those, ten studies examined the presence of a JAK-2 mutation in 1,999 blood donors. The overall proportion of JAK2 mutations was 3% (95% CI 0.60 - 6.9, I2 90.21%). Subgroup analysis revealed a prevalence of 4.7% (95% CI 2.1 - 8.0, I2 0.00%) among repeat donors with polycythemia and 2.3% (95% CI 0.0 - 7.7, I2 0.00%) among healthy ones. Only 3 (309 donors) studies reported PV prevalence, precluding a meta-analysis. CONCLUSION: The prevalence of the JAK2 mutation among blood donors is similar to the general population's but slightly higher among repeat donors with elevated hematocrit. Further research is necessary to establish definitive upper hemoglobin limits for donor deferral.PROSPERO No.: CRD42023456878.