For patients with diabetes, keeping track of blood sugar levels is critical. Luckily, for most patients, simple hand-held meters make it easy, and almost painless, to track.

What many people may not realize is that physicians often turn to these handy little meters, too, generally for quick measurements in patients undergoing surgery. Convenient and quick, yes, but is it a good thing to use a home meter in the operating room? According to a new University of Florida study, the answer is no. Inaccuracies in the devices can lead to harmful treatment errors, particularly ones resulting in very low blood sugar values.

While useful in home settings, the meters are prone to errors from a number of factors, including the presence of other chemicals or medications in the blood, and health conditions such as anemia. This can cause problems in hospital settings. If a meter gives an inaccurately high reading, for example, doctors might unnecessarily give a patient insulin to lower blood glucose, but that can make the levels truly too low and cause detrimental effects on the central nervous system. On the other hand, too-high levels can impair wound healing and alter consciousness.

One Centers for Disease Control and Prevention study found that on average, readings from some over-the-counter devices differed by as much as thirty-two percent from values obtained in a central laboratory.

Although the Food and Drug Administration has approved these meters for home use, they are not tested for use in hospitals. Now, the researchers are calling for better regulation of these meters and greater awareness of the issue among physicians. They also advise docs to rely more on lab tests and less on meter readings.

Concerned about how your blood glucose is tested in the hospital? Ask your doctor. The more informed you are, the better.