Pneumococcal Antigen in Serum (Mass Concentration)
This test detects the presence of pneumococcal bacteria in your blood serum, which can help identify infections caused by *Streptococcus pneumoniae* (pneumococcus). Early detection may guide treatment decisions.
["Assists in diagnosing pneumococcal bloodstream infections quickly."]
Key facts at a glance
- LOINC
- 24023-4
- Short code
- Deprecated S pneum3 Ab Ser-mCnc
- Synonyms
- Deprecated S pneum3 Ab 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
- 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
What This Test Measures
The test measures the mass concentration of pneumococcal antigens in your serum. These antigens are specific proteins produced by the bacteria, allowing the lab to identify active infection. The method used may involve immunoassay techniques to detect these proteins with high sensitivity.
Why It’s Done
Your healthcare provider may order this test if you have symptoms of pneumonia, sepsis, or other serious infections, especially if you’re at higher risk (e.g., elderly, immunocompromised, or with chronic health conditions). It helps differentiate bacterial infections from other causes.
Sample Collection and Preparation
A blood sample is drawn from a vein, typically in your arm. The blood is processed to separate serum (the liquid part without clots) for testing. This serum is then analyzed in a lab using specialized immunoassay methods to detect pneumococcal antigens.
What to Expect Before the Test
No special preparation is usually needed, but inform your provider about any medications (especially antibiotics) or recent illnesses you’ve had. Avoid alcohol or strenuous activity 24 hours before the test if advised.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
◆Associated findings1
Short name
Serum Pneumococcal Antigen
Frequently asked questions
A positive result strongly suggests active pneumococcal infection, which may require immediate treatment with antibiotics targeting *Streptococcus pneumoniae*. Results can help guide decisions about hospitalization, intravenous antibiotics, or monitoring for complications like meningitis or pneumonia.
A positive result indicates the presence of pneumococcal antigens in your blood, strongly suggesting an active infection caused by *Streptococcus pneumoniae*. This can prompt your doctor to start targeted antibiotic treatment right away.
No, this test is typically used alongside other tests (like blood cultures or chest X-rays) to confirm or support a diagnosis. It’s most useful for rapid identification in high-risk patients where prompt treatment is critical.
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