In the paired test performed at the evening and in the morning, the blood sugar is measured in the evening between 9 and midnight, approximately 3–4 hours after your last meal, and then again when you get up in the morning, at least 8 hours since your last meal and before breakfast.
If you use mealtime insulin, its duration of action should be over 3–4 hours after your evening meal. In this case, the tests carried out at the evening and in the morning indicate any night-time changes in your blood sugar and the effectiveness of the basal insulin.
The bedtime/morning checks show how your own or injected insulin is able to control the release of sugar from your liver into blood circulation during the night. If the difference between bedtime and morning is more than 2–3 mmol/l, it may be necessary to alter the treatment.
In type 2 diabetes insulin resistance, the blood sugar level typically tires to increase overnight. Equally, if the basal insulin dose in insulin therapy is too small or if it wears out, the blood sugar level becomes high in the morning. The basal insulin therapy is adjusted on the basis of the checks performed at the evening and in the morning.
When it comes to the treatment of type 1 diabetes or another form of insulin-dependent diabetes, use of glucose sensor has largely replaced the evening/morning blood sugar tests. Glucose sensor makes it easier to better track the way the blood sugar behaves during the night.