The other test that is critical in managing HIV and understanding how it is affecting you and your body, is the CD4 or T-cell count.
CD4 cells are a critical part of your immune system. They are infected and destroyed by HIV. The numbers of CD4 cells vary on a regular basis and are influenced by a variety of other factors apart from HIV e.g. in the case of another infection such as the flu, levels of stress. Sometimes, in HIV infection they can be depleted to such dangerous levels that they are unable to play their part in helping your immune system work properly.
A CD4 count test looks at the effect of HIV on your immune system and can tell you how much damage has been done to your immune system. If a significant amount of damage has occurred, you could be susceptible to opportunistic infections.
A general guide to CD4 test results is:
- 500 to 1,350 CD4 is the “normal” range for adults;
- Between 500 and 250 CD4 cells indicates some damage but it is unlikely you will be at risk of major opportunistic infections; and
- Less than 250 CD4 indicates more serious immune system damage and suggests that you could be at risk of serious opportunistic infections.
CD4 percentages measure the proportion of CD4 cells in every 100 lymphocytes (white blood cells that include T-cells and B-CellsOne of the two major classes of lymphocytes, B lymphocytes are blood cells of the immune system, derived from the bone marrow and spleen; they are involved in the production of antibodies. During infections, these cells are transformed into plasma cells that produce large quantities of antibody directed at specific pathogens. When antibodies bind to foreign proteins, such as those that occur naturally on the surfaces of bacteria, they mark the foreign cells for consumption by other cells of the immune system. This transformation occurs through interactions with various types of T cells and other components of the immune system. In persons living with AIDS, the functional ability of both the B and the T lymphocytes is damaged, with the T lymphocytes being the principal site of infection by HIV.). The CD4 number is calculated by determining the percentage of total lymphocytes that are of the CD4 type and then calculating that number. The percentage can indicate how stable the CD4 count is in relation to changes in the total lymphocyte count. Together with 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. and actual CD4 cell tests, it’s another result that is used by your doctor to assist in determining your optimal treatment strategies.