In vitro 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?



  • Newsletter Issue 10, Q2 2015
    pdf, 490kb

    This issue includes the new streamlined approach, abbreviated procedure, interested in Ebola? Find what the WHO PQ Dx team has been doing in the field of Ebola Virus Disease (EVD) IVDs.

Contact us

Prequalification Team - Diagnostics
Regulation of Medicines and other Health Technologies
Department of Essential Medicines and Health Products
World Health Organization
20 Avenue Appia
1211, Geneva 27