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HIV p24 Antigen Antibody Screening/Confirmation Test (Serum/Plasma)

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

This test detects antibodies to the p24 protein of the human immunodeficiency virus (HIV), which helps screen for or confirm HIV infection.

Quick summary

["This test helps determine if you have been exposed to HIV, the virus that causes AIDS."]

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

Key facts at a glance

LOINC
40437-6
Short code
HIV1 p24 Ab SerPl Ql IA
Synonyms
HIV1 p24 Ab SerPl 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 This Test Measures

The test looks for antibodies produced by your immune system in response to the p24 protein of HIV. Antibodies are proteins your body makes to fight infections. If your body has been exposed to HIV, these antibodies may be present in your blood or plasma.

Why It’s Ordered

Your healthcare provider may order this test if you have symptoms of HIV, such as fever, fatigue, or swollen lymph nodes, or if you’ve had unprotected sex or shared needles with someone who may have HIV. It’s also used as part of routine testing for people at higher risk of infection.

How the Test Works

The test uses a blood sample (collected from your vein) to detect antibodies against the p24 protein. The sample is processed in a lab and analyzed using an immunoassay method, which identifies the presence of these antibodies with high sensitivity and specificity.

Sample Collection and Preparation

A small amount of blood is drawn from your arm into a tube. The blood is then separated into plasma or serum for testing. This process is quick and typically done in a healthcare setting.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Positive results indicate exposure to HIV and may require further testing to confirm infection. Negative results suggest no current HIV antibodies, but HIV can still be present if testing was done too early after exposure. Follow-up testing may be recommended if symptoms or risk factors are present.

Short name

HIV p24 Antibody Test

Frequently asked questions

How long does it take to get results?
Results are usually available within 1 to 3 business days, depending on your lab’s processing schedule. Your healthcare provider will discuss the results with you.
What does a positive result mean?
A positive result means your blood test detected antibodies to the p24 protein of HIV, suggesting you may have been infected. This does not confirm HIV infection alone—additional confirmatory tests are needed to diagnose HIV.
Can I have false positives or false negatives?
False positives are rare but possible, especially if you’ve recently been exposed to other infections. False negatives can occur if testing was done too soon after exposure. If your test is negative but you suspect HIV exposure, retesting after 3 months is recommended.
  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