For instance, the bedtime test tells whether the dose of Humalog or Regular taken for the dinner meal has done its job. The breakfast reading is also critical in that it controls most of the rest of the day. If the morning blood sugar is high, it is very hard to control readings through most of the rest of the day.
Many people find that additional tests help.
Blood sugars done 2 hours after a meal let you know immediately if the insulin dose taken for that meal was adequate, especially with Humalog insulin. An occasional 2 a.m. reading helps keep the overnight insulin finely tuned and prevents nighttime lows.