Glicemia

Glicemia, or blood glucose concentration, is a key measure of energy metabolism in humans. It reflects the balance between dietary glucose intake, hepatic glucose production, and peripheral glucose utilization. In healthy adults, fasting glicemia typically ranges from 70 to 99 mg/dL (3.9–5.5 mmol/L). After a meal, levels rise and are usually below 140 mg/dL (7.8 mmol/L) two hours postprandially.

Measurement and interpretation: Glicemia is reported in mg/dL or mmol/L and can be measured in plasma, serum, or capillary blood. Laboratory tests use plasma glucose; home glucometers use capillary blood. For long-term assessment, HbA1c is expressed as a percentage and reflects average glucose over about three months.

Normal and dysglycemia: Normal fasting glicemia is under 100 mg/dL (5.5 mmol/L). Prediabetes includes fasting 100–125 mg/dL or 2-hour post-load 140–199 mg/dL or HbA1c 5.7–6.4%. Diabetes is diagnosed by fasting ≥126 mg/dL, 2-hour post-load ≥200 mg/dL, random ≥200 mg/dL with symptoms, or HbA1c ≥6.5%.

Regulation and physiology: Insulin lowers glicemia by promoting glucose uptake and storage, while glucagon and other hormones raise it by stimulating hepatic glucose production. The liver, muscle, and adipose tissue are central to these processes.

Clinical relevance: Chronic hyperglycemia is associated with complications such as retinopathy, nephropathy, neuropathy, and cardiovascular disease. Hypoglycemia (<70 mg/dL) is a serious risk, especially in people using insulin or certain medications.

Monitoring and management: Monitoring methods include fasting plasma glucose, oral glucose tolerance tests, HbA1c, and continuous glucose monitoring. Individual targets depend on age, pregnancy, and comorbidities.