Abstract
Fasting glycemia reflects basal metabolic state and thus its information value substantially differs from glycemia values during the day. The fasting glycemia is predominantly determined by glucose production in hepatic cells.
Management of the fasting glycemia is the first step. While the fasting glycemia is diagnostic for prediabetic state (impaired fasting glucose) and diabetes mellitus, the postload glycemia is in addition to diabetes mellitus diagnostic also for the impaired glucose tolerance.
Higher value of postload glycemia is a risk factor for the impaired glucose tolerance and diabetes mellitus and for vascular complications in patients with impaired glucose tolerance and type 1 and type 2 diabetes mellitus. We should manage the postload glycemia in patients with normal fasting glycemia and high blood level of glycated hemoglobin HbA1c.
The level of hemoglobin A1c is determined by glycemia. The moderately elevated hemoglobin A1c is caused mainly by postload glycemia; highly elevated hemoglobin A1c is caused mainly by fasting glycemia as a product of more intensive glucose output by the liver during the night.