Most reliable test for the screening of diabetes mellitus among the following is

The measurement of glucose levels in random blood samples is considered unsatisfactory for epidemiological useThe fasting value alone is considered less reliable since true fasting cannot be assured and spurious diagnosis of diabetes may readily occur.For epidemiological purposes, the 2-hour value after 75gm oral glucose may be used either alone or with the fasting value.Park 23re pg: 395