- Fasting and prep
- No fasting needed. Follow the instructions on your lab order.
- Turnaround
- Usually 1 to 3 days. A reactive screen goes on to confirmation testing, which can add several days.
- Also called
- hiv 1/2 antigen antibody, hiv combo test, fourth generation hiv test, hiv screening, hiv rna test
What it measures
After infection, p24 antigen rises first, then antibodies build over the following weeks. The CDC says a lab-based antigen/antibody test on blood from a vein can usually detect HIV 18 to 45 days after exposure. An HIV RNA test (nucleic acid test, or NAT) finds the virus itself and can usually detect HIV 10 to 33 days after exposure, so clinicians use it for very recent exposures or symptoms of early infection.
Who should consider it
- Everyone ages 13 to 64 at least once, per CDC
- People with a new partner, multiple partners, or a partner living with HIV
- Anyone who shares needles or other drug equipment
- People starting or taking PrEP (they need regular testing)
- Anyone who is pregnant or planning pregnancy
How to read your result
- Nonreactive (negative) means the test found no HIV antibodies or antigen at the time of the draw.
- A negative result during the window period can miss a recent infection. Retest after the window period if you had an exposure.
- A reactive (positive) screen does not diagnose HIV by itself. The lab runs a second test to confirm, and false positives do happen.
- An HIV RNA test helps when an exposure was very recent or when early infection symptoms appear, such as fever, rash, and sore throat.
Reference ranges differ between labs. Use the range printed on your own report.
When to get care right away. If you had a possible HIV exposure in the last 72 hours, go to an urgent care, emergency room, or sexual health clinic today and ask about PEP (post-exposure prevention medicine). PEP works best when started as soon as possible, and a home or online test cannot replace it.
What to do next
If your result is reactive, wait for confirmation and connect with a clinician or HIV care program right away. Treatment today lets people with HIV live long, healthy lives, and an undetectable viral load means the virus does not pass to sexual partners. Many health departments offer free testing, care linkage, and help telling partners.
Where to order HIV test
These sellers include an independent physician order. You pay online and visit a partner lab. Availability, price, and lab network vary, so confirm at checkout.
Private MD Labs
Online lab seller- Order
- Every order reviewed by a physician. Says you pay $1 to start and the rest after results.
- Results
- Secure online portal with plain-English explanations. Says many results arrive overnight.
HealthLabs
Online lab seller- Order
- Online or by phone. No doctor referral or insurance needed.
- Results
- Secure HealthLabs account. Says 1 to 3 business days.
Walk-In Lab
Online lab seller- Order
- Online, no insurance or doctor order needed. Shows a $6 physician fee per order on popular tests.
- Results
- Online account. Turnaround not stated on its homepage.
Quest Health
Lab-run- Order
- Buy online and book a Quest appointment. An independent provider is involved.
- Results
- Online as soon as ready, with an email alert. Provider discussion included at no extra cost.
Seller details come from each seller's own site and can change. Confirm price, lab location, and state availability at checkout.
Ordering several tests? Plan them together · Filter all sellers
Questions people ask
How long after exposure is an HIV test accurate?
The CDC says a lab antigen/antibody blood test can usually detect HIV 18 to 45 days after exposure, and a nucleic acid test 10 to 33 days after. If you test negative inside that range, test again after it ends.
What is the difference between an HIV antibody test and a 4th generation test?
An antibody test looks only for antibodies, which take longer to appear. A 4th generation test also looks for p24 antigen, so it turns positive sooner.
What should I do right after a possible exposure?
Go to a clinic, urgent care, or emergency room within 72 hours and ask about PEP. Testing comes later. PEP has to start fast to work.
Can I order an HIV test without a doctor?
Yes. Online sellers include a physician order, and you give blood at a partner lab. Many health departments and community clinics also test for free.
Related tests
- STD test panelChecks for several common sexually transmitted infections at once.
- Syphilis testScreens for syphilis and confirms a positive with a second test.
- Hepatitis C testScreens for hepatitis C and checks whether the virus is active.
- Hepatitis B surface antigenShows whether you currently have a hepatitis B infection.
We may earn a commission if you buy through links on this page, at no extra cost to you. This page is education, not medical advice. How we make money.