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A viral loadA measurement of the quantity of HIV RNA in the blood. Viral load blood test results are expressed as the number of copies (of HIV) per milliliter of blood plasma. test is a simple blood test that measures the amount of HIV in your bloodstream. Knowing how much HIV is present is an indicator of how active the virusA small infective organism which is incapable of reproducing outside a host cell. is and the risk of future damage to the immune system. The test can also determine how well your treatments are working or whether you might like to consider starting treatments.

What do the results mean?

‘Undetectable’ viral load

One result you can get back from a viral load test result is ‘undetectable’. This means that HIV is either not present or present, but in very small amounts (below the capacity of current commercial tests to accurately measure; below 40-50 copies). The virus at such levels is replicating so slowly that little, if any, damage will be happening to your CD4 cells and immune system and there is also less chance of developing resistanceHIV which has mutated and is less susceptible to the effects of one or more anti-HIV drugs is said to be resistant.. It is important to remember that you can still pass HIV through sharing needles or having unprotected sex.

Viral load tests tell you how much virus is in your blood. But HIV is also present in other body fluids, including semen, vaginal fluids and CSF (cerebrospinal fluid)—the fluid which protects your brain. The level of virus in your blood is often different to the amounts in other body fluids. This difference can be caused by a number of factors.

For this reason, blood viral load tests should not be used to judge the likelihood of HIV transmission. It is possible to have low or undetectable blood viral load, but higher levels in semen or vaginal fluids.

While research suggests an undetectable viral load reduces the risk of HIV transmission, an undetectable viral load has not yet been proven to completely eliminate the risk of transmitting the virus. The use of viral load in prevention is not a substitute for safe sex.

HIV infects cells which remain inactive or ‘resting’ in lymph glands and has also been shown to infect small amounts of other types of cells. This HIV is not measured by plasma viral load. This HIV is not reached by treatments; as long as it remains in the ‘resting cells’ in lymph glands, it does not reproduce nor do any damage. To totally cure or eradicate HIV, you would need to also eradicate the virus in these ‘resting cells’. So far, this has not been possible.

Detectable viral load results

You will often be told that your viral load result is ‘high’ e.g. more than 100,000, ‘moderate’ e.g. 10,000 to 100,000 or ‘low’ e.g. less than 10,000 copies. On their own your viral load results are no cause for alarm. For example, a high viral load result does not mean that you are going to be sick tomorrow.

Your viral load level is a rough guide to the likelihood of future damage to the immune system. So if your viral load is high it means that future damage is more likely. If it is low or undetectable it means future damage is less likely.

Next steps