ASO Test: Strep Throat and Scarlet Fever Diagnosis

ASO stands for antistreptolysin O. It is a blood test measuring the body's immune response to Streptococcus pyogenes (bacteria causing strep throat and scarlet fever). The test measures antibodies against streptolysin O, a protein produced by the bacteria.

Interpretation

• Elevated ASO levels may indicate current or recent streptococcal infection.
• Also used to monitor antibiotic treatment effectiveness.
• Other conditions (rheumatic fever, glomerulonephritis) can cause elevated levels, so results must be interpreted with clinical presentation and other lab findings.