As previously mentioned, apart from the type 1 disease, which has an acute onset, diabetes, especially type 2, is in most cases detected accidentally many years after the beginning of the disease (for example during surgery) or during laboratory tests. The fasting blood sugar level can only be an indicative index, but to aid diagnosis there are precise criteria set at an international level, based on specific fasting blood sugar values repeated over time, or based on certain changes in blood sugar in the space of 3 hours after sugar intake (the test used is the glucose load curve (Oral Glucose Tolerance Test-OGTT), usually using 75 g of glucose.
Laboratory tests helpful in diagnosis are the plasma C-peptide dosage (baseline or after stimulation with glucagon), which is a marker of beta-cell function, and the search for specific antibodies that act as autoimmunity markers (ICA, IA-2, IM, GADA).
In addition to the diagnostic criteria for diabetes in the strict sense, it should also be remembered that there are criteria indicative of other changes in sugar metabolism. These changes, commonly known as “pre-diabetes”, diagnosed using OGTT, are Impaired Fasting Glucose-IFG) and Impaired Glucose Tolerance-IGT): they do not constitute a medical condition but indicate a high risk of developing diabetes and an increased risk of cardiovascular events, and are often associated with other issues such as dyslipidemia, excess weight and obesity.
Once the disease has been established, it is clearly important to prevent and slow the progression of the damage, by carefully checking the metabolic picture and the possible impact of other potentially contributing factors (such as blood pressure, body weight and abdominal fat). Of particular importance is the periodic checking of laboratory tests, which must include, along with blood sugar, blood count and eg. urine, glycated haemoglobin – HbA1c, which is the most indicative marker of the glycemic trend over time, renal and hepatic function indices, cholesterol (total, HDL and LDL) and triglycerides. Moreover, even in the absence of symptoms, adequate specialised monitoring of the target organs is necessary, with the appropriate periodic diagnostic instrumental investigations.