Seroprevalence of antistreptolysin o antibodies in a tertiary health care centre in north India

Background: A raised Antistreptolysin O titre (ASO) level is one of the most relevant retrospective serological indices of antecedent Group A-Beta Hemolytic Streptococci (GAS) infection. A single titre of more than 200 IU/ml is considered as a raised value. Serum ASO titre is raised when there is an infection of any organ of the body by GAS,or less commonly, group C or G Streptococcus, especially in patients suspected of having a non suppurative sequel to this infection. Methods: A retrospective study was done on the sera samples received in the Department of Microbiology, PGIMS Rohtak, Haryana for the detection of ASO, over a period of two years. The test was carried out by latex agglutination rapid test kit by Aspen. Results: A total of 4063 samples were received in the laboratory during the study period. Of these, 832 (20.4%) were found to be positive for the presence of ASO having titre of >200 IU/mL. Conclusion: The prevalence of ASO was found to be highest in the age group 0-20.The presence of elevated streptococcal antibody titres in such a population reflects a high background prevalence of streptococcal infections. Thus, determination of ASO antibodies should be taken into consideration when evaluating the role of group A streptococcus in non-purulent complications of infections.