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Blood Group A/B Antibody Titration (Serum/Plasma)

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

This test measures the levels of antibodies (A or B) in your blood that may affect blood compatibility during transfusions.

Quick summary

["Helps ensure safe blood matching for transfusions by checking for unexpected antibodies."]

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

Key facts at a glance

LOINC
61406-5
Short code
XXX blood group Ab Titr SerPl
Synonyms
XXX blood group Ab Titr SerPl
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
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 Matters for Transfusions

Blood transfusions require a precise match between your blood type and the donated blood to prevent adverse reactions. This test identifies if you have antibodies against A or B antigens, which could cause complications if not detected.

What to Expect During the Test

A small blood sample is drawn from your arm. The sample is processed to separate serum or plasma, then tested for specific antibodies using a standardized method. Results are typically available within 24 hours.

How the Results Are Used

Your healthcare provider will use these results to determine if you’re compatible with donated blood of type A or B. If antibodies are found, they may recommend alternative blood types or special precautions during transfusions.

Common Causes for This Test

This test is often ordered before blood transfusions, especially if you’ve had previous reactions, are pregnant, or have a history of blood type mismatches.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance: Preventing Transfusion Reactions

Short name

A/B Antibody Test

Frequently asked questions

What does a positive or negative result mean?
A positive result indicates the presence of antibodies against A or B antigens, which could cause a reaction if incompatible blood is transfused. A negative result means no detectable antibodies, suggesting compatibility with standard A or B blood types.
How long will I need to wait for results?
Results are usually available within 24 hours, but timing may vary depending on lab processing. Your doctor will contact you once they’re ready.
Can I eat or drink before this test?
No special preparation is needed. You can eat and drink normally before the blood draw, but avoid smoking or caffeine for 30 minutes before the test if instructed by your provider.
  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