Objective: (1) to evaluate the prevalence of diabetes mellitus in the studied population at Nguyen Tri Phuong hospital (Ho Chi Minh City), with diagnosis made by criteria of fasting plasma glucose, HbA1c, and two hour plasma glucose in an oral glucose tolerance test; (2) to determine which test or which combination of tests could yield diabetes prevalence close to that given by gold standard when all of these above-mentioned criteria were met.