The Anti Streptolysin O (ASO), Quantitative Test is a blood test that measures the level of Anti Streptolysin O (ASO) antibodies in the blood. It helps determine whether a person has had a recent infection caused by Group A Streptococcus bacteria, which can lead to complications such as rheumatic fever and post-streptococcal glomerulonephritis (kidney inflammation).
This test is commonly recommended when symptoms or medical history suggest a recent streptococcal infection and helps support the diagnosis of post-streptococcal complications.
1.Anti Streptolysin O (ASO)
Measures antibodies made against the Streptolysin O toxin of Group A Streptococcus bacteria, showing a recent or past strep infection.
Also known as: ASO Test, ASO Titre Test, Anti-Streptolysin O Antibody Test, Streptolysin O Antibody Test, Quantitative ASO Test
The Anti Streptolysin O (ASO), Quantitative Blood Test measures the concentration of antibodies produced by the immune system against Streptolysin O, a toxin released by Group A Streptococcus (Streptococcus pyogenes) bacteria.
After a streptococcal infection such as strep throat or scarlet fever, the body produces ASO antibodies to fight the bacteria. Elevated ASO levels indicate a recent or previous streptococcal infection but do not necessarily confirm an active infection.
The ASO test is often used alongside clinical evaluation and other laboratory tests to identify complications that may develop after a streptococcal infection.
The test measures the level of ASO antibodies present in the bloodstream. ASO is an antibody produced by the immune system in response to the Streptolysin O toxin released by Group A Streptococcus bacteria.
Elevated ASO levels may indicate:
Normal or low ASO levels may suggest:
ASO levels should always be interpreted together with symptoms, medical history, and other laboratory findings.
Doctors may recommend an ASO Test to:
The test may be advised if you have:
Benefits of the ASO Test:
An ASO Test may be recommended for:
The test requires a blood sample collected from a vein.
Before the test:
| Parameter | Normal range |
|---|---|
| Anti Streptolysin O (ASO) | Typically less than 200 IU/mL (may vary by age and laboratory) |
| Note | Reference ranges may vary depending on age, laboratory methods, and clinical guidelines. Elevated ASO levels indicate a recent immune response to Streptococcus bacteria and should always be interpreted by a qualified healthcare professional along with symptoms and other test results. |
Reference ranges can differ between labs. Your report shows the range used by the lab.
The Anti Streptolysin O (ASO), Quantitative Test is a blood test that measures ASO antibodies to determine whether you have had a recent Group A Streptococcal infection.
It helps diagnose complications that can occur after streptococcal infections, including rheumatic fever and post-streptococcal glomerulonephritis.
No. Fasting is generally not required unless your healthcare provider advises otherwise.
Not necessarily. Elevated ASO levels usually indicate a recent or past streptococcal infection rather than an active infection.
| Test name | Anti Streptolysin O (ASO), Quantitative Test |
|---|---|
| Location | Chennai |
| Sample type | Blood |
| Number of parameters | 1 |
| Home sample collection | Available |
| Fasting | Not required |
| Report time | As per laboratory processing time |
| Recommended age | 2–99 years |
| Suitable for | Male & Female |
Recent strep throat, scarlet fever, rheumatic fever, and post-streptococcal kidney inflammation are common causes of elevated ASO levels.
Early treatment with antibiotics may reduce the body's antibody response, but ASO results should always be interpreted by your healthcare provider.
A healthcare professional collects a small blood sample from a vein, which is analyzed in a laboratory.
No. The ASO Test supports the diagnosis but must be interpreted along with symptoms, physical examination, and other laboratory tests.
Testing frequency depends on your symptoms, medical condition, and your doctor's recommendation. In some cases, repeat testing may be advised to monitor changes in antibody levels.
