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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 exposure to *Streptococcus pneumoniae* (pneumococcus), a common cause of pneumonia, ear infections, and other respiratory illnesses.

Quick summary

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

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

Key facts at a glance

LOINC
42990-2
Short code
M pneumo IgM Titr Plr
Synonyms
M pneumo IgM Titr Plr
Category
chemistry
Sample
fluid
Container
Sterile tube
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
CPT
82784
Specimen volume
2-5 mL
Stability
Room temperature: 2h, Refrigerated: 24h
Hemolysis max
300
TAT
4–24 hours
Order
routine

Why This Test Might Be Ordered

Your healthcare provider may recommend this test if you’ve had recent or recurring respiratory infections, if you’re at higher risk for pneumococcal infections (e.g., due to age, weakened immune system, or chronic health conditions), or if you’ve received pneumococcal vaccination and want to check antibody levels.

What to Expect Before the Test

No special preparation is needed. You’ll provide a blood sample, usually drawn from a vein in your arm. The sample is sent to a lab for analysis using an immunoassay method to detect specific IgG antibodies against pneumococcal bacteria.

What the Results Mean

Results show the concentration of IgG antibodies in your blood. Higher levels suggest your immune system has recognized and responded to the bacteria, while lower levels may indicate insufficient immunity. Your provider will interpret results in the context of your medical history and vaccination status.

Common Reasons for Testing

This test is often used to evaluate immunity after vaccination with pneumococcal conjugate or polysaccharide vaccines, monitor immune response in immunocompromised patients, or investigate unexplained recurrent infections.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

IgG Antibody to Pneumococcus

Frequently asked questions

Why might my healthcare provider ask for this test?
They may order it to confirm immunity after vaccination, assess risk for pneumococcal infections in high-risk individuals, or investigate symptoms like persistent cough, fever, or ear infections that could be linked to pneumococcal exposure.
What does a low or high antibody level mean?
A low level may indicate insufficient immunity and could prompt additional vaccination or preventive measures, while high levels suggest a strong immune response. Results alone don’t diagnose infection; they’re used alongside clinical findings.
Can I get this test at home?
No, this test requires a blood sample collected by a healthcare professional in a clinical setting. Some labs may offer at-home blood collection services, but results are typically reported through your provider’s office.
  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