Comparison of nephelometric and hemolytic techniques for determination of antistreptolysin O antibodies

The sensitivity of a newly devised nephelometric method for determining antistreptolysin O antibodies was compared with the hemolytic inhibition assay. Three hundred-thirty single serum samples from children with and without evidence of group A streptococcal infection were analyzed by the two techniques. The nephelometric method results correlated well with those of the reference test (concordance: r = 0.88). Furthermore, 134 pairs of acute and convalescent phase sera from patients with culture-proven GAS infection and 50 pairs from children who served as control subjects were examined. The nephelometric assay was more sensitive in detecting significant ASO antibody rises than the hemolytic assay. The automated nephelometric method appears to be a much simpler and sensitive procedure for testing ASO antibodies.