Test library
CD4 Monitoring Test
The CD4 count test measures the number of CD4 T lymphocytes in blood as part of monitoring immune function in HIV and other immunodeficiency conditions. It is used to track disease progression and response to care.
Order CD4 Count Test
Order online and visit a local collection site, or choose an at-home kit where available. No referral and no insurance required.
Order CD4 Count Test- Typical turnaround
- 1-3 business days
- Starting price
- From $188
- Results
- Confidential, online
Quick answer
The CD4 count test, part of a lymphocyte subset panel, measures the number of CD4 T cells in the blood. CD4 cells coordinate the immune response, and HIV targets them over time. Tracking the count helps clinicians understand immune function and guide monitoring. The test uses a blood sample and is interpreted with other results.
What this test measures
CD4 cells are a type of white blood cell that helps organize the immune response. HIV infects these cells and can gradually reduce their numbers, which weakens immunity. A CD4 count gives a snapshot of immune strength and is one of several markers used to follow HIV over time.
The lymphocyte subset panel typically measures CD3, CD4, and CD8 T cells, the CD4 to CD8 ratio, and natural killer and B cell markers such as CD16/56 and CD19. The sample is blood drawn from a vein, and the laboratory uses flow cytometry to count and identify cell types.
The test is ordered for monitoring rather than diagnosis of HIV; a separate HIV test confirms infection. It may also be used in other conditions that affect lymphocyte numbers. Results are interpreted with the person's overall health, treatment status, and other laboratory findings by a qualified healthcare provider.
- CD3 T lymphocytes
- CD4 T lymphocytes
- CD8 T lymphocytes
- CD4 to CD8 ratio
- CD16/56 natural killer cells
- CD19 B lymphocytes
- Absolute CD4 count
- CD4 percentage
Why people order this test
- Monitor immune function in people living with HIV
- Track CD4 levels over the course of care
- Assess lymphocyte subsets in immunodeficiency
- Evaluate an abnormal white blood cell count
- Follow changes during treatment with a provider
- Provide a baseline before ongoing monitoring
How to prepare
No fasting is required for this blood test. A sample is collected from a vein, usually at the arm. If the test is bundled with other panels, follow the laboratory's instructions.
Understanding your results
Results are usually reported within one to three business days. The report lists absolute counts and percentages for each lymphocyte subset. A healthcare provider interprets the numbers with the person's history and other tests.
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Frequently Asked Questions
What does a CD4 count measure?
It measures the number of CD4 T cells in the blood. These cells help coordinate the immune response, and their number is one indicator of immune function.
Does this test diagnose HIV?
No. CD4 testing is used for monitoring. HIV is diagnosed with a separate HIV test, and CD4 counts help track immune status over time.
What other cells are measured in the panel?
A lymphocyte subset panel may include CD3, CD8, the CD4 to CD8 ratio, natural killer cells, and B cells alongside the CD4 count.
How often is CD4 monitoring done?
The interval depends on the clinical situation and the person's care plan. A healthcare provider decides how often monitoring is appropriate.
Do I need to fast?
No fasting is required for this blood test unless it is combined with other tests that require it.
Ready to get tested?
Order online and visit a collection site near you, or choose a mail-in kit. No referral and no insurance required.
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