Laboratory results

The term "lab results" means the combined results of a blood test. It is recommended that people with HIV have their blood tested regularly. The laboratory values show how much virus is in your body and whether it has done any damage to your immune system.

Two laboratory values are especially important: the viral load indicates how much HIV is in your blood. The number of helper T cells indicates to what extent the immune system has already been damaged.

From these test results, your doctor can tell whether it is time to start HIV treatment or whether the treatment is working properly. If the test results show that the treatment is not working, you will need to change to a different combination of drugs.

As well as having regular tests to check how well the drugs are working, you will have other blood tests to see if HIV, or the drugs, are affecting any other parts of your body, such as your internal organs and bones.

Viral load

Viral load means the amount of HIV in the blood. The number of copies of virus per milliliter of blood plasma is measured.

The more HIV replicates itself, the higher the viral load, and therefore the greater the damage to the immune system.

For people with HIV who are not on treatment, a viral load under 10,000 is considered low, and a viral load from 50,000 to 100,000 is said to be high.

HIV therapy aims to reduce the viral load until it is no longer detectable by a normal viral load test - when the viral load drops to 20 to 50 copies of the virus per milliliter of blood.

It is important to know that the viral load can go up and down a great deal. After you are first infected, the viral load is extremely high, and then it drops again. Having another infection, such as the flu, can also cause the viral load of untreated HIV to rise.

Helper T cells

By measuring the number of helper T cells (also called CD4 cells), it is possible to determine how much HIV has already damaged your immune system. These cells play an important role in the body's own defense systems. If you have fewer helper T cells, you are more vulnerable to certain infections.

Generally, 500 to 600 helper T cells per microliter of blood is considered normal. If someone has less than 350 helper T cells per microliter, it is recommended that they begin HIV treatment if they also have accompanying illnesses.  Sometimes, people who are older might start HIV treatment earlier than at a T cell count of 350.

If someone has less than 2300  helper T cells, they are at high risk of AIDS-defining illnesses. These include certain infections that can, for example, lead to severe pneumonia and tumors.

When you begin HIV therapy, the number of helper T cells starts to rise again. The immune system recovers and your body is no longer as susceptible to AIDS-defining illnesses.

Other tests

In addition to your viral load, your doctor  will monitor other aspects of your health regularly.

Liver function tests indicate whether the medication has damaged your liver or whether you are suffering from liver inflammation (hepatitis).

Regular tests also measure fat levels in the blood, such as cholesterol, as many HIV drugs can disturb fat metabolism in the body. If that is the case, there are things you can do to deal with this, such as having a low fat diet, doing some exercise, taking blood-fat-lowering medication or changing your HIV therapy.

Blood sugar, kidney function and the level of vitamin D are measured to determine the effects that the drugs and the virus are having on the body. That way, for example, damage to inner organs or bones can be identified early, and – if necessary – treated.