The prevalence of ABO blood group antigens and antibodies in Lagos State, Nigeria.

A total of 1239 normal donors from the Lagos University Teaching Hospital (LUTH) and 111 staff of the National Institute for Medical Research (NIMR) Yaba were screened for ABO antibodies. Of the number from LUTH, 220 (17.8%) were found to be in group A, 282 (22.8%) in group B, 85 (6.9%) in group AB and 652 (52.6%) in group O. The number from NIMR consisted of 20 (18.0%) in group A, 25 (22.5%) in group B 8(7.2%) in group AB and 58 (52.3%) in group O. The mean tile avidity time of sera from 789 (62.66%) potent LUTH donors was less than 35 seconds. Only 97 (6.91%) of this reacted within 10 seconds. On the other hand, only 11(9.9%) of the NIMR sera reacted within 35 seconds and none reacted within 10 seconds. Group O individuals from LUTH and NIMR did not always have anti-A and anti-B components of their sera with equal avidity or potency. It was also observed that high avidity of antibody did not necessarily correspond with high potency. The commonest titre for group B (anti-A) sera was 256 and that for group A (anti-B) was 512. In general, anti-B titres tended to be consistently higher than anti-A. There was a bimodal peak at titres 32 and 256 in group B (anti-A) sera. This repeated itself in the anti-A component of group O sera (i.e., anti-A+B), but here the peaks occurred at 32 and 128.(ABSTRACT TRUNCATED AT 250 WORDS)