Diagnostics and Laboratory Technology

Frequently asked questions

CD4+T-Cell counting technology
  • What are CD4+ T-cells?
  • What is the CD4+ T-cell count?
  • How are CD4+ T-cells enumerated?
Viral load testing
  • What is HIV-1 Viral Load?
  • How are CD4 and HIV viral load used?
  • How is Viral Load measured?
ELISA tests
  • What is an ELISA test?
Simple/Rapid tests
  • What is a Simple/Rapid test?
  • What is the difference between a ELISA and a Simple/Rapid test?
Confirmatory assays
  • What is a Confirmatory Assay?
Window period
  • What is the "window-period" and how long is it?
Alternative specimens- whole blood, oral fluid & urine
  • Is urine or saliva feasible to use as a source of HIV detection?

Contact us

Prequalification Team - Diagnostics
Regulation of Medicines and other Health Technologies
Department of Essential Medicines and Health Products
(HIS/EMP/RHT/PQT)
World Health Organization
20 Avenue Appia
1211, Geneva 27
Switzerland
diagnostics@who.int