Iron kept blood donors eligible; everything else stayed uncertain
Seven of 38 blood-donor trials measured deferral for a low haemoglobin, and iron cut it by 61%. Haemoglobin, ferritin and a rise of about 69% in stomach complaints were all rated very uncertain.
What the study found
Iron kept donors from being turned away; the rest is uncertain
In a review of 38 blood-donor trials, oral iron reduced deferral for a low haemoglobin by 61% in the seven that measured it, the one outcome graded moderate certainty. Haemoglobin and ferritin rose and stomach complaints went up by about 69%, all rated very uncertain.
The caveat · Doses ran from 7 to 1,800 mg a day
Doses across the pooled trials ran from 7 to 1,800 milligrams of iron a day, schedules that are not clinically interchangeable. 27 of the 38 studies left out first-time donors, who are the people least likely to come back after being turned away and therefore the ones the intervention most needs to reach. The review was produced by a national blood service, which has a direct operational interest in donor retention.