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HIV Antibody and Antigen Combination Test (Serum/Plasma)

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

This test detects both HIV antibodies (indicating past or current infection) and HIV antigens (like p24 protein, which appears during acute infection). It helps confirm HIV status with high accuracy.

Quick summary

["A critical step in diagnosing HIV, often used as part of initial screening or confirmation testing."]

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

Key facts at a glance

LOINC
42627-0
Short code
HIV1 Ab CSF Ql IF
Synonyms
HIV1 Ab CSF Ql IF
Category
chemistry
Sample
csf
Container
Sterile tube
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
if
CPT
86701
Specimen volume
1-2 mL
Stability
Immediate analysis required, Refrigerated: 1h
Hemolysis max
200
TAT
4–24 hours
Order
routine

What This Test Measures

The test looks for two key markers in your blood: HIV antibodies (produced by your immune system after infection) and HIV antigens (like the p24 protein, which signals active virus presence). Together, they help determine if you have HIV, even in early stages.

Why It Matters for You

This test is essential for early detection, especially if you’ve had risk factors (like unprotected sex, shared needles, or exposure to infected blood). Early diagnosis allows for timely treatment and management.

How the Test Works

Your blood sample is tested using a sensitive immunoassay method that detects both antibodies and antigens. Results are interpreted to determine if HIV is present, even if symptoms haven’t appeared yet.

Preparation and Sample Collection

No special preparation is needed. A blood sample is drawn from your arm, and results are typically available within 24–48 hours. If you’re pregnant, this test is often recommended during routine prenatal care.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

HIV 1 Ab/Ag Combo

Frequently asked questions

Why might my doctor order this test?
Your doctor may recommend this test if you’ve had risk behaviors (like unprotected sex, shared needles, or exposure to HIV), have unexplained symptoms (like fever, fatigue, or swollen lymph nodes), or are part of a high-risk group (e.g., men who have sex with men, people with HIV-exposed infants). It’s also used for routine screening in certain populations.
What do my results mean?
A negative result means you’re not currently infected. A positive result requires confirmation with another test (like a Western blot or nucleic acid test) to confirm HIV diagnosis. Follow-up care with an infectious disease specialist is important if results are positive.
Can I get this test at home?
No, this test is typically performed in a clinical lab using a blood sample. Over-the-counter home tests for HIV antibodies only detect antibodies, not antigens, so they may miss early infection. Always consult your healthcare provider for accurate results.
  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