1. What is CD4 Count?

CD4 count is a measurement of how many CD4 immune cells (a type of white blood cell) are present in a blood sample. It's an important marker of immune system health, particularly in HIV/AIDS management.

2. How Does the Calculator Work?

The calculator uses the CD4 count formula:

Where:

• \( Total\ Lymphocytes \) — Total lymphocyte count from CBC (cells/μL)
• \( CD4\ \% \) — Percentage of lymphocytes that are CD4 cells

Explanation: The formula calculates the absolute CD4 count by multiplying the total lymphocyte count by the percentage of CD4 cells.

3. Importance of CD4 Count

Details: CD4 count is crucial for monitoring HIV progression, determining when to start antiretroviral therapy, and assessing immune system recovery during treatment.

4. Using the Calculator

Tips: Enter total lymphocyte count from CBC (in cells/μL) and CD4 percentage (as a percentage). Both values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What is a normal CD4 count?
A: In healthy adults, normal CD4 counts range from 500-1500 cells/μL. Below 200 indicates severe immune deficiency.

Q2: How often should CD4 counts be measured?
A: For HIV patients, typically every 3-6 months depending on treatment status and viral load.

Q3: Can CD4 percentage be used alone?
A: Yes, CD4% (normal 30-60%) can be used when absolute counts are unreliable (e.g., after splenectomy).

Q4: What factors can affect CD4 counts?
A: Infections, vaccinations, stress, time of day, and certain medications can cause temporary fluctuations.

Q5: Is this calculation always accurate?
A: While generally reliable, direct CD4 counting by flow cytometry is more precise than calculated estimates.