The Viral Load Test
Viral load means exactly what it sounds like -- it's an estimate of how much HIV is circulating in your blood. Generally speaking, your viral load is not considered as critical as your CD4 count in determining the health of your immune system. However, once you begin HIV treatment, it is a good measure of how well your HIV medications are working.
A viral load test measures the amount of HIV in a small amount (milliliter, or mL) of your blood. The most sensitive viral load tests currently used in clinics can detect as few as 20 copies of HIV per milliliter of blood. When your viral load test indicates that you have fewer than 20 copies/mL of HIV, your health care provider will tell you that your viral load is "below the limit of detection," or "undetectable."
This does not mean you no longer have HIV in your body. Though it is not technically impossible for someone who has an "undetectable" viral load to transmit HIV, studies show that there is virtually no risk of HIV transmission when a person's viral load is undetectable. Though it may be undetectable in your blood, HIV can hide out in other parts of your body -- called "reservoirs" -- and begin making more copies of itself were you to stop taking HIV meds. An "undetectable" viral load means that your medications are doing an excellent job of keeping HIV in check, both for purposes of your own health and for avoiding transmission to others.
Learn more about viral load tests, read stories from some of our community members about their first time reaching "undetectable," and find out more about viral suppression and HIV prevention.