Recent progress in diagnoses of diabetes and its complications

Most of diabetics have no symptoms and chemical analyses may be sole way to diagnose the disease itself and its complications. Chemical analyses are also important to assess the propriety of glycemic control during every possible treatment of diabetes. Some markers for long-term glycemic control other than glucose concentration may be also used as a screening methods for glucose intolerance. HbA1c is established for long term as a marker for glycemic control but still large interlaboratory variation is present. Fructosamine is measured by a simpler procedure but many deoxidizing materials in serum especially superoxide may interfere with the reaction. Glycated albumin should be more reliable than fructosamine but a standard method of measurement has not been established yet. The decrease in serum 1,5-anhydro-D-glucitol(1,5-AG) is very sensitive to urinary glucose excretion and may be useful as a marker of glycemic control and diagnosis of diabetes. Discrimination of Type I(IDDM) from Type II(NIDDM) in Japanese diabetic patients is sometimes very difficult and evidences of autoimmunity by anti-glutamic acid decarboxylase(GAD) antibody and of exhaustion of insulin secretion by C-peptide measurement 6min after combined infusion of 1mg of glucagon and 20ml of 50% glucose are the few methods to diagnose. Early diagnosis of diabetic complication is another important point of clinico-chemical determinations. Usually, each diabetic complication progresses in parallel. Micro-measurement of urinary transferrin is one of the most sensitive methods likewise urinary microalbumin measurement. Future measurement of advanced glycation end product (AGE) may also tell us if patients are suffering from diabetic complications or if one is suffering from diabetes or not.