ASO (Antistreptolysin-O), Qualitative
ASO is an antibody to streptococcal toxin (streptolysin-O).
The test helps determine whether the body recently had contact with streptococcal infection, even if the sore throat/scarlet fever has already resolved.
The qualitative test shows:
whether antibodies are detected or not (without a precise level)
Venous blood
- Fasting for 8-12 hours;
- water allowed;
- avoid fatty food/alcohol for 24 hours.
Medications: inform staff about antibiotic and hormone use.
Prescribed for:
- frequent sore throats, pharyngitis
- prolonged joint pain after sore throat
- suspected rheumatism
- suspected streptococcal complications
- prolonged fever after an infection
- swelling, urine changes (postsstreptococcal glomerulonephritis risk)
How it relates to streptococcus:
- ASO rises 1-3 weeks after streptococcal infection and may remain elevated for several months.
Recommended for testing:
- children and adults with frequent sore throats
- with joint pain after infection
- with suspected rheumatic complications
- with urine analysis changes after sore throat
Negative (not detected) — recent streptococcal infection is unlikely
Positive (detected) — there was contact with streptococcus (including recently)
Important: diagnosis is made by a physician based on a complex of data. With a positive result, consultation with a general practitioner is recommended, and a cardiologist/rheumatologist/nephrologist if needed.
Result on the day of the request
