Pneumococcal IgG Antibody (Serum) – Quantitative
This test measures the level of antibodies in your blood that your immune system produces in response to exposure to *Streptococcus pneumoniae* (pneumococcus), a common cause of pneumonia, meningitis, and other infections.
["It helps assess immunity after vaccination or natural infection."]
Key facts at a glance
- LOINC
- 21406-4
- Short code
- M pneumo IgM Ser Ql
- Synonyms
- M pneumo IgM Ser Ql
- Category
- chemistry
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- CPT
- 82784
- Specimen volume
- 5 mL
- Stability
- Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
- Hemolysis max
- 500
- Lipemia max
- 1000
- Icterus max
- 500
- TAT
- 4–24 hours
- Order
- routine
Why This Test Is Done
Doctors may order this test if you’ve had a recent or past infection with pneumococcus, if you’ve received the pneumococcal vaccine, or if you’re at higher risk of complications (e.g., due to weakened immunity). It can also be used to monitor immune response after vaccination.
What to Expect Before the Test
No special preparation is needed. You’ll have a small needle inserted into a vein (usually in your arm) to draw blood. The process takes about 5 minutes. If you’re nervous, let your healthcare provider know—some people use numbing cream or distraction techniques.
What the Test Results Mean
Results show the concentration of IgG antibodies against specific pneumococcal strains. Higher levels suggest your immune system is actively recognizing the bacteria. However, reference ranges vary by lab and may not apply to everyone.
Possible Results and Next Steps
If your levels are low, your doctor may recommend booster vaccines, further immune testing, or additional monitoring. If levels are high, it confirms your body is producing antibodies—but this doesn’t replace vaccination as a preventive measure.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
◆Associated findings1
Short name
IgG Antibody to Pneumococcus
Frequently asked questions
This test is primarily used to evaluate immune response to pneumococcal vaccination or natural infection. It can help identify individuals who may not have developed adequate protection, especially in high-risk groups (e.g., children, elderly, or immunocompromised patients).
No fasting is required for this blood test. However, always follow your doctor’s instructions if they’ve given specific guidelines for your test.
Yes, you can take your regular medications as usual unless your doctor advises otherwise. Some tests may have exceptions, but this one does not.
Sources
- 1
- 2Lab Tests OnlineSource
- 3
Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.
This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy