National HIV/AIDS Registry
The first AIDS case in the Philippines was recorded in 1984, with the death of a foreign national from pneumonia. In 1987, the Department of Health established the HIV/AIDS Registry , a passive form of reporting system, to help monitor the HIV epidemic in the country. Reports were received from accredited hospitals, clinics and laboratories and blood banks for HIV screening. In 1993 the National HIV Sentinel Surveillance System (NHSS) was established through the AIDS Surveillance and Education Project (ASEP), funded by the United States Agency for International Development (USAID) and technical assistance from the World Health Organization (WHO). From two sentinel cities in 1993, NHSSS gradually expanded to include 10 cities by 1996. These are the cities of Angeles, Baguio, Cagayan de Oro, Cebu, Davao, General Santos, Iloilo, Quezon , Pasay and Zamboanga.

The NHSSS has two components, serologic and behavioral. HIV serologic surveillance (HSS) was started in 1993 to provide prediodic estimates and monitor the prevalence of HIV infection among vulnerable groups in the sentinel sites. Behavioral sentinel surveillance (BSS) was introduced to NHSSS in 1997 to monitor trends in knowledge and behaviors of the vulnerable groups. Information from both the HSS and BSS could be used to focus appropriate interventions.

HSS serosurveillance (HSS) methodology entailed the collection of blood samples from 300 individuals belonging to the following high risk groups : registered female sex workers ( RFSW), and freelance sex workers ( FFSW) in all sites, men having sex with men (MSM) in Quezon and Cebu Cities, and injecting drug users (IDUs) in Cebu. IN addition, new military recruits of the Armed Forces of the Philippines were included as a surrogate group for the general population. Blood samples were tested for HIV and syphilis antibodies.