Serum immunoglobulins G, A and M in White and Black adults on the Witwatersrand.

Blood donors and hospital inpatients of the same sex and race group showed similar concentrations of serum immunoglobulins G and M. Serum IgA levels were significantly higher in three of four hospital patient groups as compared with blood donor groups matched for sex and race. Age was shown to be responsible for this difference, since on average the blood donors were younger and analysis of all subjects in age groups showed a progressive rise in IgA with increasing age. Lower IgA levels occurred in women than in men of comparable age and race group. A sex difference with higher IgM levels in women was confirmed. All values in Black adults were much higher than in Whites. It is therefore of importance to consider the ranges of values for any individual's age, sex and race when interpreting results of serum immunoglobulin assay.