Anti-Streptococcus Group A (Group A Streptococcus) Antibody, Serum Immunoassay (Confirmatory)

Why This Test Is Done

Your healthcare provider may order this test if you have symptoms like sore throat, fever, rash, or swollen lymph nodes that could be caused by a Group A Streptococcus infection. It’s also used to confirm a strep infection in people who test positive for rapid strep tests but still have symptoms or complications.

What to Expect Before the Test

No special preparation is needed. You’ll provide a blood sample, usually drawn from your arm. The test checks for antibodies (immunoglobulins) that your body makes after being exposed to Group A Streptococcus bacteria.

What the Test Results Mean

Positive results indicate your immune system has recognized Group A Streptococcus, meaning you likely had an infection at some point. Negative results suggest no recent exposure or infection. Results alone don’t confirm the current cause of symptoms—your provider will consider other factors.

Common Reasons for Testing

This test is most useful for diagnosing past infections (like scarlet fever or rheumatic fever) or confirming strep infections in cases where rapid tests were inconclusive. It’s not typically used for routine monitoring of active infections.