Guessing about blood glucose levels is completely unnecessary. Now, it’s possible to draw a very small amount of blood from your finger or other location (with some meters), and get a relatively accurate measure of blood glucose in ten seconds.

Blood glucose meters today also store historical information, which can be downloaded to a computer or transmitted to a physician’s office. More and more people with type 1 diabetes are wearing continuous glucose monitors, which sense glucose levels through a small wire inserted into the fluid just beneath the skin.

Although not fully approved for use in making treatment decisions, these monitors provide blood glucose levels anytime and can be programmed to alert the users when levels are trending higher or lower. Having an approved closed-loop system, where these monitors and an insulin pump work together to balance blood glucose levels without human involvement, is probably only a few years away.

Testing blood glucose levels is extremely important for people with type 1 diabetes because they must make real-time self-treatment decisions about food and insulin dosing based upon the result. People with type 1 should test before every meal and approximately two hours after meals with some frequency, a time frame referred to as postprandial.

They should test before exercising, before bedtime, and anytime they might sense high or low blood glucose levels. They should test anytime someone who knows them suggests they may “be low” — often they lack self awareness of hypoglycemia clues that are obvious to others. They should also test if consuming alcohol in excess, because alcohol can trigger hypoglycemia, and hypoglycemia can resemble alcohol intoxication.

Testing with type 2 diabetes usually follows a less stringent schedule — maybe only once or twice a day. More testing is recommended if low blood glucose levels are a potential side effect of medication (insulin or a few different kinds of pills).

Many people with type 2 diabetes wouldn’t think of testing more often than their doctor prescribes, but one of the great values of home blood glucose testing is looking for patterns. For instance, you can bet there are certain foods that have a dramatic impact on your blood glucose levels, but you can’t know which ones without doing some self-experimentation by testing.

Most type 2 medications aren’t appropriate for resolving incidental hyperglycemia like insulin can, but you can certainly change your behavior to compensate in the future. If you find by some extra testing that Grandma’s recipe for rice pudding sends your blood glucose to 320 mg/dl, you could stop eating Grandma’s rice pudding.

Your doctor may give you a funny look, but think about asking for a few more testing strips each month so you can take advantage of this remarkable technology to better control blood glucose levels.