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Serum or plasma mass concentration of pneumococcal polysaccharide antigen (13-valent conjugate vaccine type)

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

This test measures the amount of pneumococcal polysaccharide antigen in your blood, which may help assess immune response after vaccination or detect certain infections caused by *Streptococcus pneumoniae* bacteria.

Quick summary

["Checks if your body produced enough antibodies after a pneumococcal vaccine."]

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

Key facts at a glance

LOINC
46205-1
Short code
S pneum IgG Ser-mCnc
Synonyms
S pneum IgG Ser-mCnc
Category
coagulation
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 Might Be Ordered

Your healthcare provider may recommend this test if you’ve received a 13-valent pneumococcal conjugate vaccine (PCV13) and want to confirm your immune response. It could also be used in research or clinical studies evaluating vaccine effectiveness.

What to Expect Before the Test

No special preparation is needed. A small blood sample will be drawn from a vein in your arm, similar to other routine blood tests. The sample is processed to measure the antigen concentration.

What the Results Mean

Results are typically reported as a mass concentration value (e.g., micrograms per milliliter). Higher levels may indicate a strong immune response, while lower or absent levels suggest insufficient antibody production.

Common Causes of Abnormal Results

Low or absent levels may occur if the vaccine did not stimulate enough immune response, or if the test is used in research contexts where baseline antigen presence varies. High levels could be relevant in specific clinical studies.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance: Limited Routine Use

Short name

Pneumococcal Antigen (Serum/Plasma)

Frequently asked questions

What does a positive or negative result indicate?
A positive result (detectable antigen) may suggest recent infection or residual antigen post-vaccination, but this test is not typically used for diagnosing active pneumococcal infections. Negative results in vaccinated individuals often reflect adequate immune response.
Could this test detect pneumococcal pneumonia?
No, this test specifically measures polysaccharide antigen, not bacterial DNA or clinical symptoms. Pneumonia diagnosis usually relies on symptoms, imaging, or other lab tests like blood cultures.
Is this test covered by insurance?
Coverage depends on your insurance plan and clinical indication. If ordered for research or vaccine monitoring, confirm with your provider or insurance company before testing.
  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