Understanding HIV-Related Lab Tests II: Viral Load, Resistance and Tropism
July 15, 2014
Table of Contents
Having regular lab tests is a necessary part of caring for your health. If you are living with HIV (HIV+), lab tests are especially important tools that help you and your health care provider keep track of how you are doing in the following areas:
Immune System Status
Viral load is the amount (number of copies) of HIV in your bloodstream. Since HIV is a RNA virus, viral load is also called HIV RNA. Viral load can be measured by several different lab tests: a polymerase chain reaction (PCR) test, a branched DNA (bDNA) test, or a nucleic acid sequence-based assay (NASBA). All these tests are accurate, but each has a different way to measure the amount of virus. It is best to stick with the same kind of test and not switch among them or it will be difficult to compare results over time.
Viral load results are reported as copies of HIV in one milliliter of blood. The lower the number, the less virus there is in your blood. Numbers can range from about one million copies to as few as 50 copies. If you have fewer than 50 copies, your health care provider may tell you that your results are "undetectable."
Being undetectable is a great result because it means your virus is under control. However, undetectable does not mean that you have been cured of HIV or that you cannot pass it to others. It just means that there is not enough HIV in your bloodstream for the test to measure. It is also important to know that labs that test viral load have different cut-offs below which they cannot detect HIV. For example: you could have 35 copies of HIV in your blood, and in lab #1, which cannot detect any HIV below 50 copies, your viral load would be considered 'undetectable.' However, in lab #2, which cannot detect any HIV below 20 copies, your viral load would be considered detectable and would report that you have a viral load of 35.
Viral load tests are an important tool to:
One goal of HIV treatment is to keep viral load levels as low as possible for as long as possible. This gives you the best chance of staying healthy. With effective HIV treatment regimens, viral load can be reduced to undetectable in many people. This is a great result. It means that your HIV drugs are working and you are doing a great job taking them. However, HIV is still in your body, hiding in an inactive state and not reproducing. If you stop taking your HIV drugs, the virus usually comes out of hiding and starts reproducing; then your viral load will go up.
When Should You Get a Viral Load Test?
If your drug regimen is working, your viral load should become undetectable within six months of starting treatment. If this does not happen, if your viral load stays detectable on stable therapy, or if your viral load keeps increasing, it can signal that your drug regimen is not controlling HIV as well as it should. It is important that you and your health care provider discuss all possible reasons (e.g., problems with your body's ability to absorb the drug, problems sticking to your regimen, drug resistance) and take steps to correct the problem. These steps may include additional testing and considering changing HIV drugs.
This article was provided by The Well Project. Visit The Well Project's Web site to learn more about their resources and initiatives for women living with HIV. The Well Project shares its content with TheBody.com to ensure all people have access to the highest quality treatment information available. The Well Project receives no advertising revenue from TheBody.com or the advertisers on this site. No advertiser on this site has any editorial input into The Well Project's content.
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