Changing treatment if your viral load becomes detectable

The goal of HIV treatment is to reduce your viral load to an ‘undetectable’ level. All viral load tests have a cut-off point below which they cannot reliably detect HIV. This is called the limit of detection. Tests used most commonly in the UK have a lower limit of detection of either 40 or 50 copies/ml, but there are some very sensitive tests that can measure below 20 copies/ml. If your viral load is below 50, it is usually said to be undetectable.

 If your viral load doesn’t fall below this level, then it’s more likely that your current HIV treatment won’t suppress HIV for long.

Occasionally, your viral load may rise a little above 40 to 50 before dropping down to undetectable levels on the next test. These changes are called ‘blips’ and mean that you should have your viral load retested as soon as possible. Blips are often due to a problem with the testing equipment, but could be a warning sign of other problems, such as treatment failure, drug interactions, poor adherence or illness.

If your viral load has fallen below 40 to 50, and then increases to above 40 to 50 on two consecutive tests, it means that your treatment is no longer suppressing HIV effectively. You may find that your CD4 cell count starts to fall, which will increase your risk of becoming ill because of HIV.

If your treatment fails to get your viral load below 40 to 50, or it rebounds above this level, there’s also a risk that you will develop resistance to some or all of the anti-HIV drugs you are taking.

If your current HIV treatment is not suppressing your viral load to undetectable levels, your doctor will probably recommend that you change to a different regimen.

If you have two viral load tests at least a month apart and both show that your viral load is above 400, a treatment change should be considered. Before changing your treatment, it’s recommended that you have a resistance test to see which of your drugs isn’t working and to help you choose replacement drugs.

Anti-HIV drugs have to be taken at the right time, every day, to work properly (this is called adherence). If you have been having problems with adherence for any reason, talk to your doctor about which combinations fit in with the way you live your life.

This content was checked for accuracy at the time it was written. It may have been superseded by more recent developments. NAM recommends checking whether this is the most current information when making decisions that may affect your health.