The linkage of DHS HIV test results to the full DHS survey record (without personal identifiers) allows for an in-depth analysis of the sociodemographic and behavioral factors associated with HIV infection. Datasets, which include test results that can be linked to other variables in the DHS or AIS, are available for research and study.
Traditionally, HIV prevalence estimates have been derived from sentinel surveillance systems that monitored HIV rates among pregnant women and high-risk populations. By collecting blood for HIV testing from representative samples of the population of women and men in a country, MEASURE DHS can provide nationally representative estimates of HIV prevalence rates.
Both sentinel surveillance and population-based sources of prevalence data can and should be used to track HIV epidemics. Population-based testing can only be undertaken every 3 to 5 years in most countries, because of the size and cost of the surveys. Sentinel surveillance testing is often reported annually, and provides a good benchmark for measuring progress over short time periods.
In addition, population-based testing is dependent on the population's willingness to be voluntarily tested for HIV. In cases where the characteristics of those who agreed to be tested are different from those who refused testing, bias may result. Analysis of non-response conducted for most DHS surveys with HIV testing show minimal bias.
The DHS HIV testing protocol provides for informed, anonymous, and voluntary testing of women and men, usually age 15-49. The testing protocol undergoes a host country ethical review. The testing is simple; blood spots are collected on filter paper from a finger prick and transported to a laboratory for testing. The laboratory protocol includes an initial ELISA test, and then retesting of all positive tests and 5-10 percent of the negative tests with a second ELISA. For those with discordant results on the two ELISA tests, a new ELISA or a Western Blot is performed.
Since the testing is anonymous, survey respondents cannot be provided with their results. However, all respondents are given educational materials and offered referrals for free voluntary counseling and testing (VCT). In some countries, mobile VCT teams follow-up after interviewers and test willing DHS respondents.