An HIV RNA test, also called a viral load test, is used to determine if a person has recently contracted the human immunodeficiency virus (HIV), to confirm a result from another HIV test, or to determine how much of the virus is in a person with a known HIV infection. The test examines a blood sample for genetic material (ribonucleic acid, or RNA) from the HIV virus.

While the HIV RNA test is able to detect the virus within a smaller window of time after exposure than other HIV tests, it is not often used for initial screening because it is expensive and offers only a minor time difference over the more often used antigen/antibody test.

Read on to learn why you might take an HIV RNA test, what to expect when you take it, and how it compares with other HIV tests.

Why Take an HIV RNA Test?

This type of HIV test is not often used as an initial screening test but may be useful under certain circumstances.

Recent High-Risk Exposure

For some people who have had recent exposure to someone with HIV, this test has a window period that can detect the presence of the virus sooner than other tests (between 10 days and 33 days after infection).

An RNA test can be used in instances in which a patient has recently experienced high-risk exposure and has symptoms.

HIV Confirmation Testing

An HIV RNA test can be administered to confirm the positive result of an HIV screening test (such as a rapid or home test). It can also be used to further evaluate a situation in which the patient's antigen result was positive but the antibodies to HIV result was negative.

If your initial screening was done in a healthcare setting, you will likely receive a confirmation test automatically. Sometimes, another blood sample needs to be drawn.

Eliminate False Results

The HIV RNA test can also be used to eliminate false-positive HIV screening test results. These are test results that indicate you have an infection when, in fact, you don't.

As with any lab test, different tests are subject to potential false positives or false negatives (when the test result incorrectly indicates you do not have an infection when you do). It will depend on:

• Performance of the selected test
• Variation within the test system
• Medications the patient is taking
• Health conditions affecting the immune system that the patient may not be aware of
• Technical issues

Early HIV Symptoms

If you begin to experience symptoms associated with an acute HIV infection, this type of HIV test may be recommended. Symptoms are commonly flu-like and appear about two weeks to four weeks after infection.

Monitor Viral Load

If you are living with HIV, part of managing the condition is knowing your viral load. A viral load test can help confirm the amount of the virus in your body after being diagnosed with HIV.

The first viral load HIV RNA test can be administered between two and eight weeks after an HIV diagnosis to establish the viral load.

Taking the test again every three to four months is also recommended to monitor how well treatment is working. If the selected treatment is effective, a decline in the viral load is expected over the course of four to six months.

How HIV RNA Tests Compare With Other HIV Tests

There are some key differences between HIV RNA tests and other available HIV tests, such as when you can expect results, the type of sample needed, and where the test can be performed.

HIV Antigen/Antibody Tests

HIV antigen/antibody tests are often performed first for people who may have been infected with the virus. It detects the presence of the HIV antibodies that the body produces.

Some of the antibody tests have a quick turnaround time for results and can be done at home, such as:

• Rapid HIV tests: Rather than taking a blood sample, these tests require either a finger prick or an oral fluid sample. Results take up to 30 minutes.
• Home HIV tests: There are two at-home options for HIV tests, either a rapid oral fluid sample test or a mail-in test. The rapid oral fluid test will have results in about 20 minutes. The mail-in test requires a finger prick blood sample. The sample is sent in the mail to a lab to be analyzed and a healthcare provider will give you your results. The turnaround is about five days.

HIV RNA Tests vs. HIV Antigen/Antibody Tests

A big difference between these types of tests is what the tests are meant to identify.

The HIV RNA test looks for the virus's genetic material, while the HIV antigen/antibody test looks for both HIV antibodies and the p24 antigen (a protein substance that the immune system makes to spur the creation of antibodies). It may be used as an initial screening test and can detect the virus three weeks after a person has been exposed.

What to Expect From an HIV RNA Test

There's nothing you need to do to prepare for an HIV RNA test.

To perform the test, a healthcare provider will use a needle to collect a blood sample from a vein, usually in your arm.

Results from the test may indicate:

• No virus in the blood (either because there is no virus or the virus amount is below the detection limit)
• A low viral load, which may indicate that treatment is working (if you are taking the test because you are taking medication to treat HIV)
• A high viral load, which may indicate that HIV treatment is not working well, isn't being taken, or that you may be at a higher risk for AIDS

After the test, you may experience slight discomfort and possible bruising where the needle was inserted into the arm.

Summary

The HIV RNA test is used to detect the genetic material of the HIV virus in a blood sample. This test is used for a number of purposes, including when an early infection is suspected, to confirm a positive screening test result, or to measure the viral load of a person living with HIV. A healthcare provider can help you determine if this type of test is appropriate for you.

A Word From Verywell

HIV testing is a crucial public health measure. Speak with your healthcare provider to determine your risk for an HIV infection and whether it's appropriate for you to get tested. Together, you can discuss what type of test may be appropriate (including the HIV RNA test) and how often to test for HIV.