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Human Antigen A Blood Grouping (ABO) Serology, Qualitative

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

This test determines your blood type (A, B, AB, or O) by checking for the presence of specific antigens on your red blood cells.

Quick summary

["Knowing your blood type helps ensure safe blood transfusions and informs decisions about certain medical treatments."]

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

Key facts at a glance

LOINC
43102-3
Short code
Hu3 Ab Ser Ql
Synonyms
Hu3 Ab Ser Ql
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 in Daily Life

Your blood type is a fundamental part of your medical identity. It’s used during surgeries, blood transfusions, and even some pregnancy-related care. This test is often done as part of routine blood work or before procedures requiring blood products.

How the Test Works

A small sample of your blood is mixed with antibodies that react with A and B antigens. If your blood reacts with either antibody, it confirms your blood type. The result is reported as A, B, AB, or O, with Rh factor (positive or negative) if tested.

When You Might Need This Test

You may need this test if you’re preparing for surgery, planning a pregnancy, receiving blood transfusions, or if your doctor suspects a blood-related condition. Some vaccines or medications may also require it.

What to Expect Before the Test

No special preparation is needed. You can eat, drink, or take medications as usual. Bring any recent blood test results if your doctor requests them.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Blood type is critical for compatibility during transfusions. Mismatched blood can cause severe reactions, including anemia or even life-threatening conditions. It also plays a role in pregnancy risks (like Rh incompatibility) and certain hereditary conditions.

Short name

ABO Blood Type Test

Frequently asked questions

What does a positive or negative result mean?
A positive result means your blood contains the antigens tested (A, B, or both), while a negative result means they’re absent. The Rh factor (positive or negative) indicates whether you have the D antigen, which is important for Rh incompatibility risks.
How long does it take to get results?
Results are typically available within 1 to 3 business days, depending on lab processing times. Your doctor will discuss them with you during your follow-up visit.
Can blood type change over time?
No, blood type is inherited and doesn’t change throughout your life. However, certain conditions (like severe infections or autoimmune diseases) *might* temporarily alter antibody levels, but the type itself remains stable.
  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