Antistreptolysin O titre (ASOT) - serum
Last updated: Saturday, 16, June, 2007
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| Item | Process |
|---|---|
| Specimen | 5-10 mL blood in plain tube. |
| Method | Inhibition of streptolysin-induced red cell lysis. |
| Reference Interval | Age dependent. In adults, typically <166 Todd units, but consult pathologist. |
| Application | To confirm exposure to Streptococcus pyogenes, in the investigation of rheumatic fever and acute glomerulonephritis. Indicated occasionally in the investigation of severe cellulitis and rarely in recurrent tonsillitis. |
| Interpretation | A high titre, or a two fold rise in titre, indicates recent infection. Antibodies are not detected until at least 3 weeks post infection. See also Antideoxyribonuclease B (AntiDNase B) antibodies - serum. |
| Reference | Martin DR. In: Stevens DL and Kaplan EL. Streptococcal Infections. Oxford University Press 2000. |