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Human Leukocyte Antigen (HLA) Antibody Screening (Serum)

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

This test checks for antibodies in your blood that may react against certain proteins found on the surface of donor cells, often used before organ transplants to ensure compatibility.

Quick summary

["Helps prevent transplant rejection by identifying potential immune responses to donor tissues."]

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

Key facts at a glance

LOINC
40734-6
Short code
HLA Ab Ser-aCnc
Synonyms
HLA Ab Ser-aCnc
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 Is Done

Doctors may order this test if you’re a potential organ transplant candidate or if you’ve had a previous transplant to monitor for immune reactions. It’s also used in blood banking to screen donor blood for compatibility with patients.

How the Test Works

A small blood sample is taken, and your serum is tested for antibodies that could attack donor cells. The test detects these antibodies using a method called **immunoassay**, which measures their presence and strength.

Sample Collection

A vein in your arm is cleaned and a needle is inserted to draw blood. You may feel a slight pinch, but it usually doesn’t cause discomfort. The blood sample is then sent to a lab for testing.

What to Expect After Testing

After your blood is drawn, you can usually return to your normal activities immediately. If you experience any bruising, swelling, or discomfort at the injection site, apply a cold compress or take pain relievers as needed.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

HLA Antibody Screen

Frequently asked questions

Positive results may indicate a higher risk of transplant rejection or graft-versus-host disease (if applicable). Doctors use these findings to adjust medications, select compatible donors, or monitor long-term immune responses.
This test helps ensure the best possible match for organ transplants by identifying potential immune conflicts before they cause complications.
What does a positive result mean?
A positive result means your blood contains antibodies that could react against donor cells, which may affect transplant compatibility. Your healthcare team will work with you to determine the next steps, such as further testing or adjusting your treatment plan.
Can I eat or drink before this test?
You can eat and drink normally before this test, as it doesn’t require fasting. However, always follow your doctor’s specific instructions for any pre-test preparations.
  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