Prevalence and titre of alpha and beta haemolysins in blood group 'O' donors in Ilorin.

Sera from 250 selected group 'O' donors were screened for anti A and anti B haemolysins. Those that were positive were titrated for haemolytic antibodies and the result read both visually and spectrophotometrically. The visual and spectrophotometric titres were then compared. The prevalence of alpha and beta haemolysin was 23.2%. Haemolytic anti B occurred twice as frequent as haemolytic anti A but the titre of haemolytic anti-A was higher than haemolytic anti-B. There was no relationship between sex and age and the prevalence of haemolysins. Significant visual titre of 8 and above was found in 18.5% of lytic anti-A and 13.2% of lytic anti-B, but the proportion of the whole study population with significant visual titre of 8 and above was low, i.e., 2.0% for anti-A and 2.8% for anti-B. On the average the spectrophotometric titres were consistently one fold higher than the visual titres.