ANTISTREPTOLYSIN O TITRE (ASOT) - serum

---

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, acute glomerulonephritis, Henoch-Schönlein purpura. 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. See also ANTIDEOXYRIBONUCLEASE B ANTIBODIES .

Reference: Ayoub EM and Harden E. In: Rose NR et al eds. Manual of Clinical Laboratory Immunology. 4th ed. ASM Press 1992.

---