Monitoring the response to the HIV/AIDS antiretroviral treatment is as important as administering the treatment. CD4 count and viral load testing are the two tests that help monitor the response during HIV care.
It is important to monitor HIV treatment progress. It will help to know whether the treatment is controlling HIV (human immunodeficiency virus) as this will check the damage that the virus is causing to the immune system.
Damage beyond a certain level is irreversible and can result in early death. It is, therefore, necessary to monitor the effects of the treatment to confirm its positive result.
Inadequate response to treatment demands a probe into the patient’s nonadherence or a change in the antiretroviral therapy treatment program.
HIV RNA (viral load) and CD4 T lymphocyte (CD4) cell count are the only two markers that tell you how the patient is responding to the antiretroviral therapy (ART) and the progress or regression of the HIV disease.
Lab Tests to Monitor Patient’s Response to HIV Treatment
The doctor monitors the patient’s response to Highly Active Antiretroviral Therapy (HAART) by measuring the viral load and the CD4 count.
Plasma HIV-1 RNA (Viral Load) Monitoring
The viral load indicates the amount or the load of the HIV genetic material in a blood sample.
It is the most important marker of the success (or failure) of ART and it is measured at the initiation of the ART and at regular sustained intervals thereafter.
This helps to know the virulence of the infection and is helpful in the selection of the initial ART drugs.
The aim of ART is primarily to bring down the viral load to undetectable levels. This should be achieved within three to six months of starting the therapy. If not, your doctor will have another look at the choice of drugs or their doses.
What does the viral load testing tell you?
Clinical trials have shown that a reduction in the viral load following ART indicates that the therapy is working well. It also signifies a reduced risk of progression to AIDS.
Viral load testing results are reported as the number of HIV RNA copies (viruses) in a milliliter of blood. The unit of measurement is “copies/mL”.
Each virus is called a “copy,” simply because the HIV multiplies by making copies of itself. This is called replicating.
When your viral load is very low at less than 200 copies per milliliter of blood or undetectable at about 40 copies/ml, your chance of transmitting HIV is greatly reduced. However, it is necessary to maintain this viral suppression.
The CD4 cell count
CD4 cells, also called T-cells or t-helper cells, are a type of white blood cells, which are responsible for organizing the response of the immune cells to infective agents like bacteria, viruses, fungi, and parasites.
The viral load tells us the amount of the virus in the body. The CD4 count tells us how healthy your immune system is or how much the virus has damaged it and whether the treatment is controlling the damage.
CD4 cells form an important constituent of the immune system and the HIV targets these cells and damages the immune system.
The normal blood range for CD4 cells is about 500-1,500. When the CD4 count falls below 200 due to damage by HIV, a person is diagnosed with AIDS.
An increase in the fallen CD4 count increases with an effective HIV treatment and indicates a successful progression of the ART.
How often to monitor?
Viral load should be checked at the beginning of the treatment and subsequently every three and then at six months after starting the treatment. Once the viral load stabilizes, it is checked at least every six months or even once a year.
However, if you have taken a vaccination ( such as a flu jab) or got over an infection, it is advisable to wait for a month.
The proper treatment regimen will bring down the viral load to a level that the blood tests cannot detect. This means that the amount of virus in the blood is below detectable levels.
However, the virus is still present in the blood and the person can still infect others. But, the risk of passing on the infection is very much reduced.
Similarly, you check the CD4 count every three to six months to see how effective the treatment and medicines for HIV/AIDS are.
You should maintain proper records of these tests, which should also include medicines that the patient takes for any other health disorder.