What are the Best Methods for Testing Blood Sugar?

Matt Brady

The traditional method of testing blood sugar is to use a meter to test blood drawn from the fingertip. More modern and less painful tests use a small laser to draw blood. Still more modern tests include devices that continuously draw small amounts of fluid from the body via electric currents. The most exact science is still the finger-prick method, but in time more noninvasive, continuous, and less painful procedures will likely become the norm for testing blood sugar.

A glucose blood test measures the amount of glucose or "sugar" in the blood.
A glucose blood test measures the amount of glucose or "sugar" in the blood.

Blood sugar meters are widely available for personal use. Today, personal meters are small, easy-to-use devices that display blood sugar levels on a digital screen. Testing blood sugar with these devices usually requires taking a sterile lancet and pricking a fingertip. The user must then dab a drop of blood onto a testing strip, which is inserted into the blood sugar meter for a reading. There are also meters which will read blood samples from other parts of the body; this is called alternate site testing. Alternate site testing can be done with the palm or forearm.

A lancet is typically used to prick a fingertip for blood sugar testing.
A lancet is typically used to prick a fingertip for blood sugar testing.

Fingertip readings are the more preferred and reliable method, as blood from that area of the body quickly shows any adjustments in blood sugar levels. Blood from the palm and the forearm, on the the other hand, is often slower to register changes in the body's overall blood sugar levels. As a result, alternate site testings are only recommended prior to meals or at least two hours after a meal has been consumed. If testing for hypoglycemia, fingertip readings are always recommended over alternate sites.

Although pricking the fingertip for testing blood sugar isn't extremely painful, it isn't exactly comfortable, either. For those preferring a less painful method of extracting blood, there are blood sugar meters that use lasers to draw blood instead of a lancet. Individuals may need a doctor's prescription in order to purchase and use a laser blood sugar meter.

Wearing a device that continuously monitors glucose levels is an even more convenient method for testing blood sugar. Many such devices can be worn around the wrist; they send out tiny electric currents that extract glucose through the skin. The method is a relatively painless way of testing blood sugar. It also has the upside of continuously running tests throughout the day. The one drawback is that such tests aren't yet proven to be as accurate as drawing blood from a fingertip.

Another way of continuously testing blood sugar is to insert a catheter into the skin that draws small amounts of blood over a period of time. The catheter is connected to a meter which is able to provide continuous readings. This method is useful for those who need to keep an extra-close watch on their blood sugar levels. It's also useful for doctors who might want to see how blood sugar levels in patients fluctuate over time.

A person with diabetes checking her blood glucose levels.
A person with diabetes checking her blood glucose levels.

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Discussion Comments


Many diabetics I know use insulin pumps which, in addition to constantly testing the body's blood sugar, also continuously give the body enough insulin to match the current blood sugar level. While maybe not the absolute most exact science, I imagine it is safer than anything else when used in the long term.

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