Skip to content

IgG Antibody to Streptococcus Pneumoniae (Serum)

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

This test measures the level of antibodies (IgG) your body produces in response to Streptococcus pneumoniae, a common bacteria that can cause infections like pneumonia, sinusitis, or ear infections.

Quick summary

["Helps assess past exposure to pneumococcal bacteria and may guide vaccination decisions."]

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

Key facts at a glance

LOINC
47338-9
Short code
Deprecated S pneum22 IgG 2:1 Ser-Rto
Synonyms
Deprecated S pneum22 IgG 2:1 Ser-Rto
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 have a history of pneumococcal infections, are at higher risk (e.g., due to weakened immune system, chronic illness, or age), or if symptoms like fever, cough, or difficulty breathing suggest possible infection.

What to Expect Before the Test

No special preparation is needed. You’ll have a small needle inserted into your arm to draw a blood sample. The process takes a few minutes, and you may feel a brief pinch. The blood sample is sent to a lab for testing.

What the Results Mean

A positive result indicates your body has produced antibodies against pneumococcal bacteria, suggesting past infection or vaccination. A negative result means no detectable antibodies, which may prompt further evaluation or vaccination.

Common Reasons for Testing

This test is often used to evaluate immune response after vaccination, monitor recurrent infections, or assess risk in high-risk individuals before procedures that may increase infection risk.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Anti-Strep IgG

Frequently asked questions

What does a positive result mean?
A positive result means your body has produced antibodies against pneumococcal bacteria, which may mean you’ve had the infection before or have been vaccinated. This does not guarantee immunity but can help guide future prevention strategies.
How long does it take to get results?
Results are typically available within 1–3 business days, depending on your lab’s processing time. Your healthcare provider will discuss the results with you during your follow-up visit.
Can I get vaccinated if my test is negative?
Yes, if your test is negative, your healthcare provider may recommend pneumococcal vaccination (such as Pneumovax or Prevnar) to protect against pneumococcal infections, especially if you’re at higher risk.
  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