Estimating the probability of a blood donation adverse event based on 1000 interviewed whole-blood donors

BACKGROUND: Estimating the probability that a donor will have or not have an adverse event is useful for staff knowledge to give blood donors reassurance upon request. STUDY DESIGN AND METHODS: One-thousand donors from the general donor pool were interviewed for seven potential adverse events 3 weeks after a 525-mL whole-blood phlebotomy. The four most common adverse events were bruise (22.7%), sore arm (10.0%), fatigue (7.8%), and donor reaction (7.0%). A stepwise logistic regression analysis was performed based on five donor characteristics that were studied: age, weight, sex, race, and first-time donor status. The contribution of each significant or marginally significant factor to each adverse event was quantified. RESULTS: For donor reaction, weight (p < 0.0001) and age (p = 0.015) were significant contributors, and first-time donor status (p = 0.054) was a marginally significant contributor. An equation was derived, and the donor reaction rate can be estimated for a group based on the donor's weight, age, and first-time donor status. Similar analyses were performed for fatigue, sore arm, and bruise. CONCLUSION: Based on the derived formulas and with the use of a spreadsheet, data can be entered and the probability that a donor will have (or not have) a donor reaction, fatigue, sore arm, or bruise can be estimated.