Main causes of pre-donation deferral of prospective blood donors in the Singapore Blood Transfusion Service.

A retrospective study of the main causes of pre-donation deferral of prospective blood donors in the Singapore Blood Transfusion Service was carried out. Computerised records of all pre-donation deferrals from 1 January 1988 to 31 December 1991 were studied. A total of 278,401 pre-donation screening interviews were carried out during this period. Forty thousand one hundred and sixty-three or 14.4% of these transactions resulted in deferral of prospective blood donors either temporarily or permanently. Analysis of the deferrals showed that the top ten defined causes were: recent ingestion of medication; influenza; low haemoglobin level; a raised blood pressure; recent sexual exposure in high-risk activity; being underweight; Hepatitis B carrier status; recent history of measles, chickenpox or other infections; tattoos, ear-piercing or acupuncture in the preceding six months; and presenting for a subsequent donation too soon. To protect blood donors and recipients, stringent donor screening criteria are necessary. Modifying physical criteria could lower deferral rates but must be preceded by studies to ensure that donors do not suffer ill-effects. Increased public education on common causes of donor deferral may also lower deferral rates by allowing prospective donors to "pre-screen" themselves. However, one-to-one medical screening and appropriate counselling are still the best means for accepting or deferring blood donors in the Singapore setting.