Antistreptolysin O

Description

Overview of Antistreptolysin O (ASO) Test

The Antistreptolysin O (ASO) test is a blood test used to detect antibodies against streptolysin ... O, a toxin produced by Group A Streptococcus bacteria. It helps diagnose recent streptococcal infections, which can lead to complications such as rheumatic fever, glomerulonephritis, and scarlet fever.

Why is the ASO Test Done?

Doctors recommend the ASO test if a patient has symptoms of a previous strep infection, including joint pain, swelling, kidney issues, or heart inflammation. It helps confirm if a recent streptococcal infection is causing these conditions.

Normal Range of ASO Test

• Adults & Children: Typically less than 200 IU/mL
• Children under 5 years: Less than 100 IU/mL
  Higher values indicate a recent or ongoing streptococcal infection.

Before the Test

• No special fasting is required.
• Avoid excessive physical activity before the test.
• Inform your doctor about any medications you are taking.

Test Procedure

• A blood sample is drawn from a vein.
• The sample is analyzed for ASO antibodies.
• Results are usually available within 24-48 hours.

Interpretation of Results

• Elevated ASO levels suggest a recent streptococcal infection.
• Persistent high levels may indicate ongoing autoimmune reactions linked to strep infections.

Next Steps

If ASO levels are high, further tests like throat cultures, ESR, or CRP tests may be needed to determine the severity of infection and inflammation. Treatment may include antibiotics to prevent complications.