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ID:29 Anti-Streptolysin O titre (ASO)
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DescriptionGroup A streptococci (Streptococcus pyogenes) produces streptolysin which is a cytolysin. Infected patients mount an immune response to streptolysin O which can be detected 1 week and peaks 2-4 weeks after the infection. In patients without complications or reinfections the anti-streptolysin O (ASO) titre falls to pre-infection levels within 6-12 months. Elevated ASO titres are seen in 80-85% of patients with rheumatic fever and 95% of patients with post-streptococcal glomerulonephritis.
IndicationAny condition associated with infection by streptoccocus pyogenes e.g. rheumatic fever, nephritis, arthritis etc.
Additional InfoMeasurement can be useful diagnostically if recent infection with streptococci is known to be important in aetiology. Diseases include rheumatic fever, post streptococcal glomerulonephritis and scarlet fever.
Concurrent Testsna
Dietary Requirementsna
InterpretationA rise in ASO titre above 408 U/mL is associated with recent strep infection. Elevated ASO titres are seen in 80-85% of patients with rheumatic fever and 95% of patients with post-streptococcal glomerulonephritis.

DepartmentClinical Immunology
SampleBlood
TubeSerum Gel
Tube Picture
Collection ConditionsNo restrictions
Min. Vol2 mL
Freq.Weekdays

Ref. Range (Male)<408
Ref. Range (Female) <408
Ref. Range (Paed)
Ref. Range Notes<408 IU/mL
Unitsiu/mL
IP Acute TAT- Contact Laboratory
IP Routine TAT7 days
GP Acute TAT- Contact Laboratory
GP Routine TAT7 days
Turnround CommentNA

Originally edited by : JHB. Review due on 14/09/2018 14:19:28. Published By AM on 14/09/2017 14:19:28.