Serum/plasma concentration of pneumococcal polysaccharide antibodies (qualitative or semi-quantitative screening)

What This Test Measures

This test measures the level of antibodies specific to pneumococcal polysaccharides, which are components of the bacterial cell wall. These antibodies are part of your immune system’s defense against pneumococcal infections. The test may be qualitative (yes/no presence) or semi-quantitative (approximate level of response).

Why It’s Done

Your healthcare provider may order this test if you have a history of pneumococcal infections, are at high risk for pneumonia or sepsis, or if you’ve received pneumococcal vaccination to monitor your immune response.

How It’s Performed

A blood sample is drawn from a vein in your arm. The serum or plasma is then analyzed using an immunoassay method to detect pneumococcal-specific antibodies. Results are typically reported as positive, negative, or indeterminate.

What the Results Mean

Positive results indicate the presence of antibodies, suggesting your body has mounted an immune response to pneumococcal antigens. Negative results mean no detectable antibodies were found. Interpretation depends on clinical context, such as vaccination history or symptoms.