When the body is infected with streptococci, it produces antibodies against the various antigens that the streptococci produce.<unk>  is one such antibody. A raised or rising levels can indicate past or present infection. Historically it was one of the first bacterial markers used for diagnosis and follow up of rheumatic fever or scarlet fever. Its importance in this regard has not diminished. Since these antibodies are produced as a delayed antibody reaction to the above-mentioned bacteria, there is no normal value. The presence of these antibodies indicates an exposure to these bacteria. However, as many people are exposed to these bacteria and remain asymptomatic, the mere presence of<unk>  does not indicate disease. Acceptable values, where there is no clinical suspicion of rheumatism are as follows: * Adults: less than 200 units * Children: less than 100 units This titre has a significance only if it is greatly elevated (> 200), or if a rise in titre can be demonstrated in paired blood samples taken days apart. The antibody levels begin to rise after 1 to 3 weeks of strep infection, peaks in 3 to 5 weeks and falls back to insignificant levels in 6 months. Values need to be correlated with a clinical diagnosis.
Anti-streptolysin O
Anti–Saccharomyces cerevisiae antibody
Heterophile antibody
Microantibody
Antisperm antibodies
Panel-reactive antibody
Anti-nuclear antibody
Anti-LKM antibody