TY - JOUR T1 - How to use antistreptolysin O titre JF - Archives of disease in childhood - Education & practice edition JO - Arch Dis Child Educ Pract Ed SP - 231 LP - 237 DO - 10.1136/archdischild-2013-304884 VL - 99 IS - 6 AU - E S Sen AU - A V Ramanan Y1 - 2014/12/01 UR - http://ep.bmj.com/content/99/6/231.abstract N2 - Group A streptococcus (GAS) is the cause of a wide range of acute suppurative and, following a latent period, non-suppurative diseases such as rheumatic fever and poststreptococcal glomerulonephritis. Diagnosis of the latter group requires evidence of preceding GAS infection. The bacteria produce a range of extracellular antigens, including streptolysin O, which induce an antibody response in the host. A rise in antistreptolysin O titre (ASOT) is indicative of preceding GAS infection. In clinical practice, often only a single ASOT measurement is available and its timing in relation to a possible GAS infection is unknown. Interpretation of the result in this context is liable to misdiagnosis. In order to optimise diagnosis of preceding GAS infection, at least two sequential ASOT measurements, together with simultaneous assay for anti-DNase B, a second antistreptococcal antibody, is recommended. ER -