How to measure glycemic instability?

Instability of glycemic levels is "normal" in type 1 diabetes, with differe nt levels of severity, up to the restrictive definition of brittle diabetes (repeated ketoacidosis and/or severe hypoglycemias). Quantification of gly cemic instability, in terms of intraday variability and day-to-day reproduc ibility, is advisable. Standard deviation of blood glucose, though a simple index does not discriminate between slow and brutal variations. Repartitio n of blood glucose values also only indicates dispersion. M values compares the patient values to an ideal blood glucose level, emphasizing the role o f low values. The MAGE index measures the amplitude of the largest glucose excursions, thus evaluating appropriately glycemic variability. The Low Blo od Glucose Index (LBGl) is a new index of variability emphasising las the M value) the low glycemias. Each glycemia is given a value from 0 (if greate r than or equal to 110 mg/dl) to 100 (if less than or equal to 20 mg/dl). I t thus integrates the frequency and severity of hypoglycemias. According to its authors the LBGl would be the best indicator of severe hypoglycemias. The Mean of Daily Differences (MODD) evaluates the day-to-day reproducibili ty of blood glucose values. All the above indexes could easily be incorpora ted in the programmes of large memory glucose meters.