HIV viral load: definition, process, and explanation of test results

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Definition

What is HIV viral load?

The viral count test measures how much human immunodeficiency virus (HIV) is in the blood. The viral load is first measured when you are diagnosed with HIV infection. This initial measurement serves as the baseline, and subsequent measurements are compared with the baseline measurement. Since viral load can vary from day to day, trends over time are useful in determining whether the infection is getting worse. If the viral load continues to increase over several measurements, the infection is getting worse. If the trend in viral load decreases over several measurements, it means that the infection is improving.

Virus count is measured using one of three different types of tests:

• reverse-transcriptase polymerase (RT-PCR) chain reaction test
• branched DNA (bDNA) test
• sequence-based amplification (NASBA) nucleic acid test

This test measures the amount of HIV genetic material (RNA) in the blood. However, each test gives different results from each other so it is important to use the same test all the time.

When should I take HIV viral load?

The different times you will need to take a HIV count test include:

• right after diagnosis, the so-called baseline measurement. The results of subsequent tests can be compared with that test
• every 2-8 weeks at the start of treatment or with a change in treatment. This helps assess how the drug works
• every 3-6 months or as directed by your doctor if treatment is effective

Your doctor may consider measuring your viral count along with your CD4 + count to decide when to start antiretroviral therapy.

Precautions & warnings

What should I know before taking HIV viral load?

Do not compare the results of different methods (RT-PCR, bDNA, NASBA) for measuring virus counts. It is important to use the same measurement method every time. An undetectable viral count does not mean that you no longer have HIV in your blood, it simply means that the amount of HIV in your blood is too low to be detected in a test. HIV can still be transmitted to other people even if the amount of the virus cannot be detected.

Viral count tests are not routinely used to diagnose HIV. The HIV antibody test is used for this purpose. The PCR method of viral count testing is very sensitive, which can give some false positive HIV results.

Process

What should I do before receiving HIV viral load?

You don't need to do anything before undergoing this test.

How is the HIV viral load process?

The doctor will clean a small area on your arm or elbow with an antiseptic cloth or alcohol pad. In some cases, your doctor will tie an elastic belt around your upper arm to increase blood flow so that blood can collect from the arteries much more easily. Your arm is then pricked with a needle that is inserted into the vein. The tube that collects blood is attached to the other end of the needle.

Once enough blood has been collected, the doctor will remove the needle and then put a cotton swab and bandage in place to stop the bleeding where the skin was pricked with the needle.

What should I do after receiving HIV viral load?

You will be notified when you can find out the test results. The doctor will explain the meaning of the test results and you must follow the doctor's instructions.

Explanation of the Test Results

What do my test results mean?

Test results can take up to 2 weeks.

Normal values ​​listed here — called range references — are for guidance only. This range varies from laboratory to laboratory and depends on the test method used (RT-PCR, bDNA, NASBA). Your laboratory may have different ranges for normal benchmarks. The report from the laboratory should contain the range your laboratory uses. In addition, your doctor will assess your results based on your health and other factors. This means that values ​​outside the normal values ​​listed here may still be normal for you or your laboratory.

The resulting viral count is reported as the HIV copy number in milliliters (stream / ml) of blood. Each virus is called a "copy" because HIV reproduces by making its own copy (replica).

Viral load

Normal: HIV is not detected in the blood.

Abnormal: HIV is detectable in the blood. The doctor will compare the current measurement with previous values.
If the number of viruses increases, it means that the infection is getting worse, and vice versa.