A viral load test measures how much human immunodeficiency virus (HIV) is in the blood. The test measures the amount of the genetic material (RNA) of HIV in the blood. Viral load is first measured when you are diagnosed with HIV infection. This first measurement serves as the baseline. Future viral load measurements will be compared with the baseline. With good treatment, the viral load should go down. Within a few months of treatment, the virus should become undetectable. This means there is very little virus in your blood.
Why It Is Done
A viral load test is done to watch for changes in an HIV infection. Your doctor uses it to see how well your treatment is working. This information helps guide your treatment options.
A goal of treatment is to reach an undetectable viral load. This means that the amount of the virus is too low for the test to detect. When the virus is undetectable, you cannot pass HIV to other people through sex.
How To Prepare
In general, there's nothing you have to do before this test, unless your doctor tells you to.
How It Is Done
A health professional uses a needle to take a blood sample, usually from the arm.
How It Feels
When a blood sample is taken, you may feel nothing at all from the needle. Or you might feel a quick sting or pinch.
There is very little chance of having a problem from this test. When a blood sample is taken, a small bruise may form at the site.
Each lab has a different range for what's normal. Your lab report should show the range that your lab uses for each test.
Viral load results are reported as the number of HIV copies in a milliliter (copies/mL) of blood. Each virus is called a "copy," because HIV reproduces by making copies of itself (replicating).
HIV is not detected in the blood.
HIV is detected in the blood. Your doctor will compare your current measurement with previous values.
If the viral load drops, it means that the infection is being suppressed.
An undetectable viral load result doesn't mean that you no longer have HIV in your blood. It means that the amount of HIV in the blood was too low for the test to detect.
Current as of: September 8, 2022
Author: Healthwise Staff
E. Gregory Thompson MD - Internal Medicine
Adam Husney MD - Family Medicine
Peter Shalit MD, PhD - Internal Medicine