HIV p24 Antigen in Plasma/Serum (Qualitative Immunoassay)
This test detects the presence of HIV p24 antigen in your blood or plasma, which is a protein produced by the virus shortly after infection begins.
["Helps identify early HIV infection by detecting viral proteins in your blood."]
Key facts at a glance
- LOINC
- 44872-0
- Short code
- HIV1 p24 Ag SerPl Donr Ql IA
- Synonyms
- HIV1 p24 Ag SerPl Donr Ql IA
- Category
- chemistry
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- ia
- 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 Is the Purpose of This Test?
This test is used primarily to screen for early HIV infection. It can help confirm if you’ve recently been infected with HIV, even before antibodies develop, which may take weeks to months to appear in standard antibody tests.
How Is the Test Performed?
A blood sample is drawn from a vein, usually in your arm. The sample is then tested for the presence of HIV p24 antigen using an immunoassay method, which detects specific viral proteins in your plasma or serum.
What Does a Positive Result Mean?
A positive result indicates the presence of HIV p24 antigen, suggesting recent HIV infection. This does not mean you have AIDS or advanced HIV disease, but it means you should seek medical evaluation promptly to confirm diagnosis and begin treatment if needed.
What Does a Negative Result Mean?
A negative result means the test did not detect HIV p24 antigen at the time of testing. However, HIV infection can still be present if antibodies have not yet developed. Follow-up testing may be recommended if you suspect exposure or have symptoms.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
This test is particularly useful for early detection of HIV, which is critical for starting antiretroviral therapy (ART) as soon as possible. Early treatment can significantly improve health outcomes and reduce the risk of transmitting HIV to others. It’s also valuable for monitoring in certain high-risk groups or after potential exposure.
Short name
HIV p24 Antigen Test
Frequently asked questions
How soon after exposure can this test detect HIV?
What if I have a positive result?
Can this test be used to diagnose HIV in children?
Sources
- 1
- 2Lab Tests OnlineSource
- 3
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.
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