CD4 cell count

  • Changes in CD4 cell count are helpful in showing whether or not HIV is damaging the immune system.
  • It is also helpful to calculate the CD4 percentage because this is less likely to vary between laboratories.
  • CD4 cell counts are measured by taking a small blood sample from a vein in the arm. Flow cytometry is used to determine results and specimens should be processed within 18 hours.
  • The reference range for a normal CD4 cell count will vary between laboratories, but the adult range is generally between 500 and 1500 cells/mm3.  
  • Immediately after HIV infection, the CD4 cell count is likely to fall several hundred cells below the previous normal level.
  • The average decline in CD4 cell count each year is around 40 cells/mm3. Every decrease of 100 cells/mm3 doubles the risk of developing AIDS.
  • CD4 cell count may go up and down for reasons that have nothing to do with HIV infection. Results may vary by the time of day, time of month (in women), or time of year a test is taken; recent surgery; other viral infection; corticosteroid use; and thyroid imbalance.
  • The CD4 cell count should be checked every few months to see whether it is stable or falling.
  • If the CD4 cell count falls below 200 cells/mm3, the risk of developing an opportunistic infection increases and prophylaxis against specific pathogens may be started, if available.
Community Consensus Statement on Access to HIV Treatment and its Use for Prevention

Together, we can make it happen

We can end HIV soon if people have equal access to HIV drugs as treatment and as PrEP, and have free choice over whether to take them.

Launched today, the Community Consensus Statement is a basic set of principles aimed at making sure that happens.

The Community Consensus Statement is a joint initiative of AVAC, EATG, MSMGF, GNP+, HIV i-Base, the International HIV/AIDS Alliance, ITPC and NAM/aidsmap

This content was checked for accuracy at the time it was written. It may have been superseded by more recent developments. NAM recommends checking whether this is the most current information when making decisions that may affect your health.

NAM’s information is intended to support, rather than replace, consultation with a healthcare professional. Talk to your doctor or another member of your healthcare team for advice tailored to your situation.