PURPOSE: To assess the usefulness of urine glucose testing, physician-based and self blood glucose monitoring, and assays of glycated hemoglobin in diagnosing and treating diabetes mellitus. DATA IDENTIFICATION: Relevant literature in English from 1957 through early 1988 was identified via textbooks, original research articles, and review and policy papers, supplemented by a computer-based search of the National Library of Medicine MEDLINE database. STUDY SELECTION: Articles were selected because of prominence, based on frequent citation or policy authoritativeness, and relevance to the epidemiologic and clinical constructs of this paper. RESULTS: We analyze the epidemiologic studies underlying the higher diagnostic glycemic thresholds for diabetes proposed by the National Diabetes Data Group and we suggest a diagnostic strategy in which glycated hemoglobin may substitute for glucose tolerance testing. Our section on treatment stresses matching the intensiveness of hypoglycemic therapy with the intensiveness of monitoring: emphasizing the role of self blood glucose monitoring. Our findings and recommendations are summarized in the figures and tables. CONCLUSIONS: Major advances in the diagnosis and management of diabetes have been made in the past 10 years. In particular, an array of epidemiologic studies have provided a logical basis for diagnostic standards, and two new means of assessing glycemia--glycated hemoglobin and self-monitoring of blood glucose--have become widely available. These tests allow more convenient approaches to diagnosis, and provide a fuller description of glycemia, permitting more informed and intensive therapy.