Frequently Asked Questions - Living with HIV - Lab tests

What are T Cells?

T cells play a very important role in the effective functioning of the human immune system.
T cells are important because they stimulate other immune cells to respond to infection. Without T cells, the immune system cannot protect the body against many types of germs.

What is a "CD4+ count"?

T cells can also be called CD4+ cells.

A CD4+ cell count measures the number of T cells in a cubic millilitre of blood. A measure of CD4+ cells indicates how healthy the immune system is and, in people who are HIV positive, can help to indicate how far the disease has progressed.

In a person with a healthy immune system, a CD4+ cell count generally falls between 500 and 1500. A CD4+ cell count of 200 or less in a person living with HIV may mean a higher susceptibility to opportunistic infections.

People who are HIV positive should monitor their CD4+ cell counts, and their viral load counts, regularly. Results are generally passed along and reviewed by health care professionals to support case-by-case, individualized planning in order to establish at what point an individual should consider starting or adjusting anti-HIV medications.

What is "Viral Load"?

Viral load refers to the amount of HIV in a person’s blood. It is very important that Persons living with HIV/AIDS (PWAs) monitor their viral load on a regular basis. Results of viral load testing can help indicate:

When to start, stop, or adjust HIV treatment
To what degree HIV is progressing within the body
A higher ability to transmit HIV to another person