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A CD4+ count is a blood test to determine how well the immune system is working in people who have been diagnosed with human immunodeficiency virus (HIV). CD4+ cells are a type of white blood cell. White blood cells are important in fighting infections. CD4+ cells are also called T-lymphocytes, T-cells, or T-helper cells.
HIV infects CD4+ cells. The number of CD4+ cells helps determine whether other infections (opportunistic infections) may occur. The pattern of CD4+ counts over time is more important than any single CD4+ value because the values can change from day to day. The CD4+ pattern over time shows the effect of the virus on the immune system. In people infected with HIV who are not getting treated, CD4+ counts generally decrease as HIV progresses. A low CD4+ count usually indicates a weakened immune system and a higher chance of getting opportunistic infections.
CD4+ counts are done to:
A CD4+ cell count taken at the time you are diagnosed serves as the baseline against which future CD4+ cell counts will be compared. Your CD4+ cell count is monitored every 3 to 6 months, depending on your health status, previous CD4+ cell counts, and whether you are taking antiretroviral therapy medicines.
Before you have this test, you may have the opportunity to meet with a counsellor so that you understand what the test results could mean about your HIV infection.
The health professional drawing blood will:
You may feel nothing at all from the needle puncture, or you may feel a brief sting or pinch as the needle goes through the skin. Some people feel a stinging pain while the needle is in the vein. But many people do not feel any pain (or have only minor discomfort) after the needle is positioned in the vein. The amount of pain you feel depends on the skill of the health professional drawing the blood, the condition of your veins, and your sensitivity to pain.
There is very little risk of complications from having blood drawn from a vein.
A CD4+ count is a blood test to determine how well the immune system is working in people who have been diagnosed with human immunodeficiency virus (HIV). CD4+ cell count results are generally available in 1 to 3 days, depending on the lab.
The normal values listed here—called a reference range—are just a guide. These ranges vary from lab to lab, and your lab may have a different range for what's normal. Your lab report should contain the range your lab uses. Also, your doctor will evaluate your results based on your health and other factors. This means that a value that falls outside the normal values listed here may still be normal for you or your lab.
CD4+ cell counts in people who are not infected with HIV usually range from 600 to 1,500 cells per microlitre (mcL). footnote 1
A CD4+ cell count greater than 350 but less than 500 cells/mcL means that the immune system is beginning to weaken.
A CD4+ cell count of fewer than 350 cells/mcL indicates a weak immune system and an increased risk for opportunistic infections.
A CD4+ cell count of fewer than 200 cells/mcL indicates acquired immunodeficiency syndrome (AIDS) and a high risk for opportunistic infections.
As the CD4+ count drops, it becomes more likely that acquired immunodeficiency syndrome (AIDS) will develop.
Reasons you may not be able to have the test or why the results may not be helpful include:
CitationsPagana KD, Pagana TJ (2010). Mosby's Manual of Diagnostic and Laboratory Tests, 4th ed. St. Louis: Mosby Elsevier.Canadian AIDS Treatment Information Exchange (2011). A Practical Guide to HIV Drug Treatment for People Living with HIV. 3.4, When to Start. Available online: http://www.catie.ca/en/practical-guides/practical-guide-hiv-drug-treatment-people-living-hiv/3-treating-hiv/34-when-start.Other Works ConsultedFischbach FT, Dunning MB III, eds. (2009). Manual of Laboratory and Diagnostic Tests, 8th ed. Philadelphia: Lippincott Williams and Wilkins.Pagana KD, Pagana TJ (2010). Mosby's Manual of Diagnostic and Laboratory Tests, 4th ed. St. Louis: Mosby Elsevier.U.S. Department of Health and Human Services Panel on Antiretroviral Guidelines for Adults and Adolescents (2013). Guidelines for the Use of Antiretroviral Agents in HIV-1-Infected Adults and Adolescents. Available online: http://www.aidsinfo.nih.gov/ContentFiles/AdultandAdolescentGL.pdf.
Current as ofJuly 30, 2018
Author: Healthwise StaffMedical Review: E. Gregory Thompson, MD - Internal MedicineAdam Husney, MD - Family MedicinePeter Shalit, MD, PhD - Internal Medicine, Infectious Disease
Current as of: July 30, 2018
Author: Healthwise Staff
Medical Review:E. Gregory Thompson, MD - Internal Medicine & Adam Husney, MD - Family Medicine & Peter Shalit, MD, PhD - Internal Medicine, Infectious Disease
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