Serum or plasma concentration of immunoglobulin G (IgG) antibodies to pneumococcal polysaccharides (pneumococcal antibody screening)

What This Test Measures

This test detects specific antibodies (IgG) your immune system creates in reaction to pneumococcal antigens. These antibodies are part of your body’s defense against pneumococcal bacteria, which can cause infections like pneumonia or sepsis. The test is typically performed on serum or plasma, the liquid part of blood that contains these antibodies.

Why It Might Be Ordered

Your healthcare provider may order this test if you have a history of pneumococcal infections, are at high risk for pneumococcal disease (e.g., due to weakened immune systems, chronic illnesses, or age), or if you’ve recently received a pneumococcal vaccine to monitor your immune response.

What to Expect Before the Test

No special preparation is usually needed. You may be asked to fast for 8–12 hours before the test if it involves drawing blood, but this is not always required for antibody testing. Bring any medications or questions to your appointment.

What to Expect During the Test

A healthcare professional will draw a small amount of blood from a vein in your arm. You may feel a slight pinch, but it’s generally quick and painless. The blood sample will be sent to a lab for analysis.