What is HIV - 1 RNA Virus - Quantitative - Viral Load?

Human immunodeficiency virus (HIV) is the virus that can cause acquired immunodeficiency syndrome (AIDS). This test measures the amount (viral load) of HIV genetic material (RNA) in your blood.

When you are initially infected with HIV, the virus replicates — it produces more and more copies of itself. The main target of HIV is the CD4 cells, which are a type of white blood cell that fights infections. The virus enters these cells and uses them to replicate and spread throughout your body. It moves into your lymph nodes, spleen, and other parts of your body.

In the early stages of infection, there may not be any noticeable signs or symptoms of disease or only flu-like symptoms, although the virus is usually present in high amounts. Without treatment and even when there are no symptoms, the virus continues to replicate and the viral load will increase. HIV kills your CD4 cells, so the number of CD4 cells will decrease as HIV infection progresses.

About 3-8 weeks after initial exposure to the virus, your immune system begins to produce HIV antibodies in response to the infection and suppresses the HIV viral load, decreasing it to a low level. Initial symptoms typically resolve, but your infection does not go away.

The only way to determine whether you have been infected is through HIV testing. If not detected early and treated, an HIV infection may slowly degrade your immune system. After several years and without treatment, the immune system can become so weakened that the disease begins to affect your ability to fight infections and certain cancers. Symptoms of AIDS begin to appear at this stage as your body becomes more susceptible to infections with microorganisms such as tuberculosis and fungi or other diseases such as Kaposi’s sarcoma.

When you are diagnosed, you are given antiretroviral treatments for HIV (also called highly active antiretroviral therapy or HAART) to suppress the amount of HIV virus present in your blood, limiting its ability to replicate and reducing the risk of progressing to AIDS. Evidence shows that keeping the viral load at undetectable levels decreases your risk of progressing to AIDS and greatly improves your long-term health. If you have HIV and discontinues treatment or if it loses its effectiveness, then your HIV viral load can begin to increase again.

How is the test used?

The HIV viral load test is used initially, along with a CD4 count, to determine the status of your HIV infection when you have been diagnosed with the disease. The viral load is then used to monitor the effectiveness of your antiretroviral treatment (ART) over time.

The HIV viral load may also be used to help determine whether the virus infecting you has become drug-resistant. If you do not respond well to treatment and the amount of virus continues to increase, then the virus may be resistant to that particular ART. Your treatment will then likely be modified.

HIV viral load tests are most useful when they are compared with results obtained from your earlier tests. They are used in combination with the CD4 count to monitor how effective ART is in suppressing your HIV. (For more details, see the article on the CD4 Count.) The HIV RNA test detects HIV virus genetic material and measures how many copies of HIV (viral load) are present in your blood at a particular time. It can track increases and decreases in your HIV viral load and, in conjunction with a CD4 count, be used to evaluate treatment effectiveness.