Study of streptococcal antibody (anti-streptolysin O) among healthy children in Bangladesh.

Objectives: The standard reference value of anti-streptolysin O (ASO) titre for diagnosing acute rheumatic fever (RF) in children is yet to be determined in Bangladesh. We aimed to measure the upper limit of the normal (ULN) of ASO titre among healthy children to determine the cut-off value for the diagnosis of RF in Bangladesh.

Methods: A total of 400 healthy children aged 5-15 years with no history of fever, sore throat and impetigo during the last 8 weeks of the study were enrolled. The respondents were randomly selected from an urban non-slum area, an urban slum area and a rural area of Bangladesh. ASO titre was measured using a turbidimetric immunoassay based on the principle of an agglutination reaction. The 80th percentile value was considered as the ULN of ASO titre.

Results: Approximately 55% of the children were male. The mean (SD) age of children was 9.1 (2.7) years. The ULN of ASO titre for 5-15 years aged children was 217.4 IU/mL.

Conclusion: Our reference value of ASO titre at the 80th percentile will be an essential guide for clinicians to diagnose acute RF.