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Streptococcus Group B Antibody Detection (Qualitative, Latex Agglutination Probe)

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

This test checks for antibodies against Group B Streptococcus, a type of bacteria that can sometimes affect newborns during childbirth. It helps determine if you may need additional precautions during delivery.

Quick summary

["This test assesses your immune response to Group B Streptococcus to guide prenatal care decisions."]

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

Key facts at a glance

LOINC
88277-9
Short code
Streptococcus sp tuf Bld Pos Ql Probe
Synonyms
Streptococcus sp tuf Bld Pos Ql Probe
Category
coagulation
Sample
whole-blood
Container
Lavender-top (EDTA)
Units
N/A
Ref low
0.8
Ref high
1.2
Critical range
— – 5 N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
probe
CPT
85610
SNOMED
396252006
Specimen volume
3 mL
Stability
Room temperature: 4h, Refrigerated: 24h
Hemolysis max
0
Lipemia max
0
Icterus max
0
TAT
4–24 hours
Order
routine

Why This Test Is Done

Healthcare providers may recommend this test if you are pregnant, especially during late pregnancy (around 35–37 weeks), to identify if you have antibodies against Group B Streptococcus. This helps prevent potential infections in your newborn.

What to Expect During the Test

A small blood sample is taken from your arm. The sample is then tested using a probe method to detect the presence of antibodies. Results are qualitative (positive or negative) rather than a numerical value.

How the Results Are Interpreted

A positive result means your body has detected antibodies against Group B Streptococcus. This does not necessarily mean you are currently infected but may indicate a prior exposure. A negative result means no detectable antibodies were found.

What It Means for Your Pregnancy

If your test is positive, your healthcare provider may recommend additional testing or precautions during labor, such as administering antibiotics to both you and your baby to reduce infection risk.

Reference range

INR: 0.8-1.2 (warfarin: 2.0-3.0)N/A

Specimen: whole-blood

Inform your healthcare provider if you are taking blood thinners. No special preparation required.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

Group B Streptococcus (GBS) Antibody Screen

Frequently asked questions

What does a positive result mean?
A positive result suggests your immune system has recognized Group B Streptococcus, which may have been introduced earlier in your pregnancy or through exposure. This is not the same as an active infection but is important for guiding preventive measures during delivery.
Why is this test important for my baby?
Group B Streptococcus can cause serious infections in newborns, such as pneumonia or bloodstream infections. Early detection of antibodies helps healthcare providers take extra precautions, like administering antibiotics during labor, to lower the risk of transmission to your baby.
Can I get this test done at any time during pregnancy?
This test is typically done around 35–37 weeks of pregnancy. However, your healthcare provider may recommend it earlier if they suspect you may have been exposed or if you have certain risk factors.
  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