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Pneumococcal IgG Antibody by Immunoassay (Serum/Plasma)

Published: August 9, 2026Updated: August 16, 2026

This test measures the level of antibodies (IgG) your body produces in response to infection by *Streptococcus pneumoniae* (pneumococcus), a common cause of pneumonia, meningitis, and other serious illnesses.

Quick summary

["Helps assess immunity against pneumococcal bacteria after vaccination or infection."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
22427-9
Short code
M pneumo IgM Titr Ser
Synonyms
M pneumo IgM Titr Ser
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 Matters

Pneumococcal bacteria can cause severe infections, especially in people with weakened immune systems, young children, or older adults. This test checks if your immune system has developed antibodies to protect against these bacteria, which may be important after vaccination or if you’ve had a recent infection.

When You Might Need It

Your healthcare provider may order this test if you’ve had a pneumococcal vaccine, recently had pneumonia or meningitis, or if you’re at high risk for pneumococcal infections (e.g., due to chronic health conditions). It can also help monitor immune response in certain medical settings.

What to Expect Before the Test

No special preparation is needed. You’ll provide a blood sample (serum or plasma) drawn from a vein in your arm. The test is typically done in a lab and results are ready within a few days.

What the Results Mean

Results show the concentration of IgG antibodies against pneumococcal antigens. Higher levels suggest your immune system has recognized and responded to the bacteria, while lower levels may indicate insufficient immunity or recent infection.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

IgG Antibody to Pneumococcus

Frequently asked questions

What Does This Test Detect?
This test detects IgG antibodies specific to pneumococcal bacteria, which are part of your immune defense. Elevated levels may indicate past infection or vaccination success, while low levels could signal a need for booster vaccination or further evaluation of immune function.
How Does This Compare to Other Tests?
Unlike culture tests (which identify live bacteria) or PCR tests (which detect genetic material), this test focuses on antibodies, providing insight into immune response rather than active infection status.
What If My Results Are Abnormal?
If your results are low, discuss with your doctor whether vaccination is recommended or if other immune-related tests are needed. If you’ve had recent symptoms of pneumonia or meningitis, further evaluation may be required.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

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.

Medical Disclaimer

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