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HIV p24 Antigen Antibody Screening Test (Serum/Plasma)

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

This test detects antibodies to the p24 protein of the human immunodeficiency virus (HIV). It helps screen for HIV infection by identifying your immune system’s response to the virus.

Quick summary

["This screening test helps determine if you may have been exposed to HIV."]

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

Key facts at a glance

LOINC
43011-6
Short code
HIV1 p24 Ab Ser Ql
Synonyms
HIV1 p24 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
CPT
86701
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

What This Test Measures

The p24 antigen is a protein produced by the HIV virus. Antibodies against this protein develop after infection, typically within weeks to months. This test looks for these antibodies in your blood or plasma to screen for HIV.

How the Test Works

Your blood or plasma sample is tested using an immunoassay method to detect HIV antibodies specific to the p24 protein. The test is designed to be sensitive enough to detect early signs of infection.

Why It’s Done

Healthcare providers may recommend this test if you have risk factors for HIV (e.g., unprotected sex, shared needles, or exposure to infected blood), symptoms of infection, or if you’re part of a group at higher risk. It is also used as part of routine screening in certain settings.

What to Expect Before the Test

No special preparation is needed. You may have a small needle inserted into your arm to draw blood. If you’re nervous, let your healthcare provider know—they can help make the process more comfortable.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

HIV p24 Antibody Screen

Frequently asked questions

If your test is positive, further confirmatory testing (like a Western blot or HIV RNA test) will be needed to confirm HIV infection. A positive result means you may have HIV, and immediate medical evaluation is crucial for managing the condition.
A positive screening result does not definitively diagnose HIV. Follow-up testing is required to confirm or rule out infection.
What does a positive result mean?
A positive result suggests you may have been exposed to HIV, but it does not confirm the infection alone. You will need additional testing to determine if you have HIV. Early treatment can help manage the virus and improve health outcomes.
Can I get false positives?
While rare, false positives can occur due to cross-reactivity with other infections or medications. If your screening test is positive, your healthcare provider will guide you through next steps, including confirmatory testing to ensure accuracy.
  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