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antistreptolysin-O test (ASOT, ASO, ASLT)
a streptococcal antibody test for finding and measuring serum antibodies to streptolysin-O, an exotoxin produced by most group A and some group C and G streptococci. The test is often used as an aid in the diagnosis of rheumatic fever and glomerulonephritis. A low titer of antistreptolysin-O antibody is present in most people, since streptococcal infection is common. Elevated or increasing titers indicate a recent infection.