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ASO TITRES (Streptococcal serology)

About This Test

Department: Virology and Molecular Microbiology


4ml clotted blood (1ml if paediatric), red top,


Turnaround Time: 3 days

To determine recent infection with group A beta-haemolytic streptococci (Streptococcus pyogenes)

Other Comments:

If processing is delayed, refrigeration is preferable to storage at ambient temperature. Delays of over 24 hours are undesirable

Measurement units: IU/mL
Clinical decision points: 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.
Factors known to significantly affect results: Haemolysis
Reference Lab: n/a