Description

The ASO test measures antibodies called antistreptolysin O in the blood. These antibodies are produced by the immune system in response to a toxin called streptolysin O, which is made by group A Streptococcus bacteria.

Why the ASO Test Is Important

This test helps diagnose or monitor complications that can occur after a strep infection, including:

  • Rheumatic fever – an inflammatory disease that can affect the heart, joints, skin, and brain.
  • Post-streptococcal glomerulonephritis – a kidney inflammation that may occur after a strep infection.

By measuring ASO antibodies, healthcare providers can determine whether a recent or past strep infection may be contributing to these conditions.

Fasting: Not required.