Rapid Diagnostic Tests (RDT's) are essential tools in antiretroviral treatment (ART) scale up. An important drawback to RDTs is the risk of false positive results. In 2005, MSF-Holland has therefore changed the testing algorithm to introduce a confirmation test. This proposal outlines an evaluation study of the results of the new confirmatory testing algorithm. It aims to compare the confirmatory algorithm employed by MSF-OCA to the MoH serial algorithm which is based on WHO recommendations. A secondary objective of the study is to determine if there is a correlation between kala-azar infection and risk of false positive HIV RDT results as clinicians in the projects suspect such a correlation. Furthermore, the study will look at the positive predictive value of weak test lines, which have been associated with higher risk of false positive results. Finally, the study aims to evaluate the results of a new simplified confirmation test, the dilution testing. Clients for the study will be recruited at two counseling and testing sites in Abdurafi and Humera, aiming to reach a sample size of 200 serial-algorithm positive and 200 negative samples in each site.