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Meningococcal Group B Antigen (Serum/Plasma)

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

This test measures the presence of antibodies against *Neisseria meningitidis* group B bacteria in your blood. It helps assess immunity after vaccination or exposure.

Quick summary

["This test checks if your body has developed protection against serious bacterial infections caused by group B meningococcus."]

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

Key facts at a glance

LOINC
44093-3
Short code
N men Islt Cult
Synonyms
N men Islt Cult
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
organism-specific-culture
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’ve received the meningococcal B vaccine, had recent exposure to someone with meningococcal disease, or if you’re at higher risk for infection (e.g., due to immune conditions or travel to areas with higher rates of meningococcal disease).

What to Expect Before the Test

No special preparation is needed. A blood sample will be drawn from a vein in your arm. You may feel a slight pinch, but it usually takes only a few minutes. If you’re on blood-thinning medication, let your provider know before the test.

What the Results Mean

Positive results indicate the presence of antibodies against group B meningococcus, suggesting your immune system has recognized and responded to the vaccine or infection. Negative results mean no detectable antibodies were found. Consult your provider for interpretation.

Common Causes of Positive Results

A positive result may occur after vaccination, natural infection, or exposure to the bacteria. It does not confirm active infection but indicates immune response.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance: Understanding Your Results

Short name

B Group Meningococcus Antibody

Frequently asked questions

How often do I need this test?
If you’ve received the meningococcal B vaccine, your provider may recommend follow-up testing at specific intervals (e.g., 1–2 years) to monitor antibody levels, though this is not always standard. Ask your provider about personalized recommendations.
What if my results are negative?
A negative result means no detectable antibodies were found at the time of testing. This does not mean you are immune—it may indicate you need another dose of the vaccine or further monitoring. Discuss with your provider if you’re unsure about your vaccination status.
Does this test detect active infection?
No, this test only measures antibodies, which are part of your immune response. If you suspect active meningococcal infection, seek medical attention immediately, as symptoms (e.g., high fever, stiff neck) may require urgent treatment.
  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