Streptococcus pneumoniae (pneumococcal) antibody, immunoglobulin G (IgG) concentration (serum/plasma)

Why This Test Might Be Ordered

Your healthcare provider may recommend this test if you’ve had recent symptoms of infection (like fever, cough, or trouble breathing), if you’ve been vaccinated against pneumococcus but still seem vulnerable to infections, or if you have a weakened immune system. It can also be used to monitor long-term immunity after vaccination.

What to Expect Before the Test

No special preparation is needed. You’ll typically have a small needle inserted into a vein in your arm to draw blood. The process takes about 5 minutes, and you may feel a slight pinch. If you’re nervous, let your provider know—some people use numbing cream or distraction techniques.

What the Test Results Mean

Results show the amount of IgG antibodies in your blood. Higher levels may indicate your body is actively fighting a pneumococcal infection or has been exposed recently. Lower levels could suggest poor immunity, especially if you’ve had recent vaccination. Your provider will interpret results in the context of your medical history and symptoms.

Common Reasons for Testing

This test is often used in: - Patients with recurrent infections (e.g., sinusitis, pneumonia). - Those with immune deficiencies or chronic illnesses (e.g., HIV, cancer). - People who’ve had pneumococcal vaccination but still experience infections.