Immunoassay for IgG Antibodies to Streptococcus Group B (GBS) in Serum/Plasma

Why This Test Is Done

Doctors may order this test if you have symptoms of infection (such as fever, fatigue, or muscle aches), if you’re pregnant and at higher risk for complications, or if you’ve been exposed to Group B strep. It can also help diagnose or monitor conditions linked to bacterial infections.

What to Expect Before the Test

No special preparation is needed. You’ll provide a blood sample, usually drawn from your arm. The sample is sent to a lab for testing using an immunoassay method to detect specific antibodies.

What the Test Results Mean

Positive results indicate your immune system has produced antibodies against Group B strep, suggesting past exposure or infection. Negative results mean no detectable antibodies were found. Results alone don’t confirm or rule out an active infection; they’re used alongside clinical judgment and other tests.

Common Causes of Positive Results

A positive result may occur after exposure to Group B strep, from a past infection, or in people with chronic conditions that affect immunity. It’s not definitive proof of active infection but can signal a need for further evaluation.