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Antibody to Streptococcus pneumoniae (Serum) – Qualitative

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

This test detects whether your body has produced antibodies against the bacteria *Streptococcus pneumoniae*, which can cause serious infections like pneumonia, meningitis, or bloodstream infections.

Quick summary

["Helps identify past or current exposure to *Streptococcus pneumoniae* bacteria."]

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

Key facts at a glance

LOINC
49805-5
Short code
Deprecated S pneum23 Ab sp1 Ser IA-aCnc
Synonyms
Deprecated S pneum23 Ab sp1 Ser IA-aCnc
Category
coagulation
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
ia
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 looks for the presence of antibodies (proteins made by your immune system) that target *Streptococcus pneumoniae*. If antibodies are found, it suggests your immune system has encountered this bacterium before, either through infection or vaccination.

Why It’s Ordered

Doctors may order this test if you have symptoms of pneumonia, recurrent respiratory infections, or if you’re at higher risk (e.g., young children, elderly adults, or those with weakened immune systems). It can also help confirm a diagnosis in unclear cases.

What to Expect Before the Test

No special preparation is needed. You’ll provide a blood sample, usually drawn from your arm. The test is quick and typically done in a lab setting.

What the Results Mean

A positive result means antibodies are present, indicating past exposure. A negative result suggests no current immune response to *Streptococcus pneumoniae*. Results alone don’t confirm infection—your doctor will consider symptoms and other tests.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

Strep Pneumonia Antibody (Qualitative)

Frequently asked questions

Why might my doctor ask for this test?
To assess whether you’ve been exposed to *Streptococcus pneumoniae* (e.g., after vaccination or infection) or to monitor immune response in high-risk patients.
What does a positive result imply?
It suggests your body has recognized the bacterium, but doesn’t confirm active infection. It may help guide vaccination decisions or rule out certain diagnoses.
Can this test replace other diagnostic tests?
No. It’s often used alongside other tests (like chest X-rays or cultures) to support a diagnosis of pneumonia or other infections caused by *Streptococcus pneumoniae*.
  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