RESUMO
BACKGROUND: The reliability of capillary hemoglobin (Hb) as an indicator for eligibility to donate blood is discussed controversially. Therefore, a noninvasive alternative with acceptable predictive values was established and evaluated. STUDY DESIGN AND METHODS: Donor candidates were selected according to their Hb level. The first donation was performed 6 weeks after this selection step. A venous blood sample was collected from all donors at the end of their donation and a postdonation Hb determination was performed. Donors with acceptable postdonation Hb values were permitted to donate next time without any predonation Hb measurement. Donors with low postdonation Hb values were permitted to donate only after a venous Hb measurement had shown an acceptable value. Sensitivity and specificity were determined by comparing the gold standard (i.e., venous Hb measurement) with the presented method of Hb estimation for 19,534 donors. RESULTS: Taking the postdonation Hb as an indicator for eligibility saved 97 percent of donors from being tested unnecessarily by capillary Hb measurement. This procedure resulted in a specificity of 92.6 percent and a sensitivity of 37.9 percent for Hb cutoff levels of 135 and 125 g per L for men and women, respectively. The sensitivity increased rapidly to 100 percent for Hb levels below 105 g per L. The average deviation from true Hb level was 6 g per L. CONCLUSION: The presented noninvasive method distinctly saves time and expenditure without endangering blood donors.