Diabetes Mellitus is a disorder of glucose homeostasis and monitored by measurement of:
- Blood glucose levels.
- Glycated hemoglobin (HbA1c) levels.
Blood glucose measurements are routinely done by:
- Blood sample (venous sample) in the laboratory.
- With the glucometer using capillary blood sample by finger prick.
- Venous blood glucose levels are the same as capillary blood glucose levels during fasting.
- After meals, venous blood glucose levels are ≈ 10% lower than capillary blood glucose.
- Whole blood glucose levels are 12 – 15% lower than plasma concentrations.
- Some glucometers are calibrated to report whole blood glucose.
- Most of the currently marketed glucometers give results as equivalent to venous plasma glucose.
- Laboratory methods of blood glucose measurements are more accurate than glucometer values.
- The majority of the glucometers conform to the International Organization for Standardization (ISO) standards that 95% of the readings <72 mg/dl are within 15% of the actual values and for higher glucose readings within 20% of the correct values.
- For the regular monitoring of blood glucose, glucometers are handy tools.
If the glucose readings are not fitting with the usual pattern, then recheck the glucose readings in the laboratory.
- Take the glucometer to the laboratory
- Give the blood sample for the glucose measurement in the laboratory
- Immediately check the blood glucose with the glucometer using capillary blood after finger prick.
- If the glucometer glucose values are within 15-20% of the laboratory glucose values, then the glucometer values are accurate and can be used for regular monitoring of blood glucose.
Glucometers are useful for the self-monitoring of blood glucose (SMBG) for patients with Type 1 Diabetes, Type 2 Diabetes, GDM (Gestational diabetes mellitus).