Minimum donation intervals should be reconsidered to decrease low hemoglobin deferral in whole blood donors: an observational study.

BACKGROUND: Most donor deferrals are due to low hemoglobin (Hb) levels. Previously measured Hb levels and donation intervals are known to be associated with Hb deferral. However, this relationship has never been quantified. In this study, we related the prevalence of Hb deferral to previously measured Hb levels and donation intervals. STUDY DESIGN AND METHODS: A total of 220,946 whole blood donors were categorized into groups based on their Hb level at the previous donation and on the time interval since the previous donation. For each group, the prevalence of Hb deferral was assessed. RESULTS: Hb deferral rates were higher when Hb levels at the previous donation were lower and donation intervals were shorter. With a donation interval shorter than 3 months, the prevalence of Hb deferral was below the 10% threshold only when the previous Hb level was at least 0.3 mmol/L above the cutoff level for donation. CONCLUSION: To maintain appropriate Hb levels, the minimum donation interval of 56 days is only sufficient for donors with Hb levels far above the cutoff level for donation. Protocols for minimum donation intervals should be reconsidered and may be based on previously measured Hb levels. This may result in a decrease of low Hb deferral.