Retrospective analysis of capillary hemoglobin recovery in nearly 1 200 000 blood donor returns by Pia Niittymäki, Mikko Arvas, Antti Larjo, Pirkko Mattila, Jarkko Ihalainen, Martti Syrjälä, Johanna Castrén, and Jukka Partanen BloodAdv Volume 1(14):961-967 June 13, 2017 © 2017 by The American Society of Hematology

Pia Niittymäki et al. Blood Adv 2017;1:961-967 © 2017 by The American Society of Hematology

Hemoglobin recovery curves including all donor returns, subdivided into age groups below 30 years old, 31 to 50 years old, and over 50 years old and sex. Hemoglobin recovery curves including all donor returns, subdivided into age groups below 30 years old, 31 to 50 years old, and over 50 years old and sex. The black line shows the population average. The upper panels show distributions of the donor returns. The lower panels show the average recovery of capillary Hb (∆Hb) as a function of return period (∆T in days). The 95% confidence intervals are shown as gray shading. Pia Niittymäki et al. Blood Adv 2017;1:961-967 © 2017 by The American Society of Hematology

Hemoglobin recovery curves, including all donor returns, subdivided on the basis of donation frequency. Hemoglobin recovery curves, including all donor returns, subdivided on the basis of donation frequency. Frequent donors (more than 15 for men, more than 10 for women) are shown in green, those of intermediate activity (6-15 for men, 6-10 for women) in red, and those of infrequent activity (5 or fewer for both sexes) in blue. The black line shows the population average. The upper panels show the distributions of the donor returns, and the lower panels show recovery (∆Hb) as a function of return interval (∆T in days). The 95% confidence intervals are shown as gray shading. Pia Niittymäki et al. Blood Adv 2017;1:961-967 © 2017 by The American Society of Hematology

Distribution of the number of donor returns with recovery below ∆Hb = 0 (left bars) and above ∆Hb = 0 (right bars) in 10-day return intervals. Distribution of the number of donor returns with recovery below ∆Hb = 0 (left bars) and above ∆Hb = 0 (right bars) in 10-day return intervals. Each bar is divided into age groups with color codes. Pia Niittymäki et al. Blood Adv 2017;1:961-967 © 2017 by The American Society of Hematology

Deferral rates due to low cHb as a function of time for different age groups. Deferral rates due to low cHb as a function of time for different age groups. The black line shows the population average. Pia Niittymäki et al. Blood Adv 2017;1:961-967 © 2017 by The American Society of Hematology