top of page

Anti-Streptolysin-O (ASO)

The ASO test is used for the qualitative screening and semi-quantitative determination of Anti-streptolysin O antibodies (ASO) in serum of strep infection. It helps determine strep infections. Increased levels could also cause damage to the heart and joints. RH and Kidney disease could occur if left untreated.

In infections caused by B-hemolytic streptococci, Streptolysin-O is one of the two hemolytic exotoxins liberated from the bacteria that stimulates production of ASO antibodies in the human serum. The level of these antibodies in serum reflects the severity of strep infection.

The ASO test is a stabilized, buffered suspension of latex particles coated with Streptolysin O. When this latex reagent is mixed with serum containing ASO, agglutination occurs. The latex reagent’s sensitivity yields agglutination when the ASO level is greater than 200 IU/ml, which is the level indicating disease.