HIV Monitoring Test Basics

Your HIV-positive test result only lets you know that you've been infected with HIV. To find out if it's time to get HIV treatment, you'll have to visit a health care provider and get two additional tests.

Most HIV-positive people can live many years with HIV before they need to take medications to control it. However, every person who tests HIV positive should immediately have two additional tests: a CD4 count and a viral load test. These tests are the critical measuring tools you and your health care provider will use to see what the virus is doing in (and to) your body. Your HIV specialist will also give you complete blood count test to check your overall numbers.

The CD4 Count Test

This test, also known as a "T-cell count test," gives an indication of the number of CD4 cells in your bloodstream. The more CD4 cells you have, the stronger your immune system is. After living with HIV for a while (if you don't take medications), the number of CD4 cells you have will usually fall. This is a sign that your immune system is being weakened. A normal CD4 count for someone without HIV is usually between 500 and 1,600. Experts generally agree that when your CD4 count goes below 350, you're at a high risk for developing potentially dangerous illnesses, so it's best to begin taking HIV medications before your CD4 count hits 350.

CD4 Count Explained

Healthy-    500-1,660

Borderline Low-  350- 500

Low200-350

Extremely Dangerous0- 200

The Viral Load Test

Viral load tests provide 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. Current viral load tests can detect as few as 50 copies of HIV per milliliter of blood. When your viral load test indicates that you have fewer than 50 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 that you no longer have HIV in your body. Even someone who has an "undetectable" viral load can transmit HIV. However, an "undetectable" viral load means that your medications are doing an excellent job of keeping HIV in check.

HIV Drug Resistance Testing

Besides a CD4 count and viral load test, your HIV specialist will look at your overall health with a general blood count test. You may also be given an HIV drug resistance test. A resistance test will tell you if your HIV has already become resistant to any HIV medications. How could this happen? The person you got HIV from may have been on HIV treatment and his or her virus may have become resistant to one or more HIV medications. Transmitted along with HIV was resistance to certain drugs. So before you take treatment, you'll want to be sure your HIV is not resistant to any drugs.