Anti streptolysin O reaction provides useful information for diagnosis and monitoring of human streptococcal infections such as in tonsillitis, otitis, erysipelas scarlet fever, as well.as connective tissue diseases like rheumatic fever, or glomerulonephritis. This test is a sensitive test for recent streptococcal infection. A rise in titer begins about one week after infection and peaks two to four weeks later. Streptolysin O Antibody (ASO) titer does not rise with cutaneous infections. In the absence of complications or reinfection, the titer will fall to preinfection levels within 6 to 12 months. Over 80% of patients with acute rheumatic fever and 95% of patients with acute glomerulonephritis have elevated titers of ASO.
Elevated levels of ASO indicate:
- Active streptococcal infection.
- Bacterial endocarditis: an inflammation in the lining of the heart.
- Poststreptococcal glomerulonephritis: an infection in the kidney.
- Rheumatic fever: a disease that may affect the heart and kidneys.
- Scarlet fever: an infection involving the throat and tongue that causes fever, rash, and rapid pulse.
