Serum or Plasma Immunoassay for Antibodies to Group B Streptococcus (GBS) – Quantitative
This test measures the amount of antibodies your body produces in response to Group B Streptococcus (GBS), a type of bacteria that can sometimes affect newborns during childbirth.
["Knowing your GBS antibody levels helps assess your risk of transmitting infection to your baby during delivery."]
Key facts at a glance
- LOINC
- 1006-6
- Short code
- DAT IgG-Sp Reag RBC-Imp
- Synonyms
- DAT IgG-Sp Reag RBC-Imp
- Category
- chemistry
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Ref low
- 4.2
- Ref high
- 5.9
- Critical range
- 2 N/A – 7 N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- CPT
- 85041
- SNOMED
- 900000000000003001
- 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 Is Done
Doctors may order this test if you are pregnant, especially in the third trimester, or if you have a history of GBS infection. It helps determine whether you have enough antibodies to protect your baby from GBS-related complications, such as pneumonia or meningitis.
What to Expect Before the Test
You will likely have a simple blood draw from a vein in your arm. The process is quick and usually painless. No special preparation is needed, but inform your healthcare provider if you are on any medications or have allergies.
How the Test Results Are Used
Results help guide decisions about prenatal care, such as whether you need additional testing (like a vaginal swab) or if you may need antibiotics during labor to reduce the risk of passing GBS to your baby.
What the Results Mean
Higher antibody levels suggest your body has built up immunity to GBS. Lower levels may indicate a higher risk of transmitting the bacteria to your baby, prompting further evaluation.
Reference range
Adult males: 4.2-5.9; Females: 3.8-5.1 x 10^12/LN/A
No special preparation required. Stay well hydrated.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
◆Associated findings1
Short name
GBS Antibody Level
Frequently asked questions
Why might my GBS antibody test results be important?
What if my antibody levels are low?
How often should I get this test?
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 17, 2026. · Read our editorial policy