Anti-Streptolysin O (ASO)

About Test

The Anti-Streptolysin O (ASO) assay evaluates the level of antibodies produced by the immune system in response to infection with Group A Streptococcus bacteria. Streptolysin O is a toxin produced by these bacteria, and the body generates antibodies, specifically anti-streptolysin O antibodies, to neutralize it. This test is crucial in diagnosing recent or past streptococcal infections, particularly those affecting the throat (such as strep throat) or causing complications like rheumatic fever or glomerulonephritis. Elevated levels of ASO antibodies typically indicate recent streptococcal infection, while declining levels may suggest resolution of infection or indicate the presence of a chronic condition, such as rheumatic fever. Physicians often order ASO testing in conjunction with other tests, such as throat cultures or rapid antigen tests, to confirm a diagnosis of streptococcal infection and guide appropriate treatment with antibiotics. Monitoring ASO levels helps healthcare providers assess the effectiveness of treatment and prevent potential complications associated with untreated streptococcal infections.