ARVs have to be used with appropriate and cost-effective diagnostics. Diagnostic technologies are important to monitor the progression of the disease, the safety and efficacy of the treatment and the development of resistance.

Since 1988, WHO has provided objective assessments of commercially available HIV test kits. This ongoing evaluation programme is coordinated by the WHO Department of Essential Health Technologies in collaboration with the UNAIDS Secretariat.

In 1989, WHO established a HIV test kit bulk-procurement scheme, which is now operated in collaboration with other UN agencies. The aim is to provide national AIDS programmes, blood transfusion services, large hospitals, nongovernmental organizations, reference laboratories, UN agencies, donor-supported AIDS projects, and regulatory authorities in developing countries with high quality tests at reasonable cost. All HIV tests available through the scheme have been successfully evaluated by the WHO evaluation programme and meet specific, rigorous criteria. Manufacturers of test kits that have met the criteria are invited to make their quotations in a selective tender process. In addition to the assay performance other aspects such as production capacity, distribution and service networks, patent issues, shelf life and storage conditions, are considered. This process has enabled the UN agencies to offer high quality tests at reduced prices, resulting in considerable annual savings to countries.

The test kits listed in chapter 4 are reviewed annually and cover the three broad categories, including simple/rapid tests, ELISA tests and supplemental tests.

The demand for simple/rapid HIV tests has increased and a wide range of high quality simple/rapid tests are available. These are easy-to-use tests that require little or no equipment and limited training to perform and can provide accurate same-day results. This makes them particularly suitable for use in voluntary counselling and testing (VCT) centres and in antenatal clinics for prevention of mother to child transmission of HIV. When initial tests are reactive for HIV, confirmation of the test results is needed to rule out any false positive results.

The existing systems for assessment and procurement of HIV test kits are being expanded to include technologies used to monitor ARV therapy (CD4+ counts and viral load) and drug resistance.

An overview of types of CD4+ T-cell enumeration technologies available are given in Annex 1A, whilst information on HIV viral load technologies is given in Annex 1B. Please note that this information is regularly updated and available at: http://www.who.int/eht/Main_areas de work/BTS/HIV_Diagnostics/HIV_Test_Kit Evaluation.htm#Reports

Additional documents with relevant information related to diagnostics are listed in Annex 3.