Pneumococcal IgG Antibody (Serum) – Qualitative Immunoassay

What This Test Measures

The test detects IgG antibodies specific to pneumococcal antigens. These antibodies are part of your immune response and indicate whether your body has encountered the bacteria before, either through illness or vaccination. The result is qualitative—meaning it only tells you if antibodies are present (positive) or absent (negative).

Why It Might Be Ordered

Your healthcare provider may recommend this test if you have a history of pneumococcal infections, live in a setting with high exposure (e.g., nursing homes, military bases), or are at increased risk for complications from pneumococcal disease. It can also help assess immunity after receiving the pneumococcal vaccine.

How the Test Works

A small blood sample is drawn, and the serum (liquid part of blood) is tested using an immunoassay method to identify pneumococcal-specific IgG antibodies. This method detects the antibodies without measuring their exact concentration, so it’s useful for determining presence rather than precise levels.

What to Expect Before the Test

No special preparation is needed. You may have some mild discomfort or bruising at the injection site, but this usually fades quickly. If you’re on blood-thinning medication, let your provider know before the test.