I have several home glucose monitors, and I can test at the same time from the same finger and get an 80 mg/dl [4.4 mmol/L] difference between the three monitors, while at other times they’ll all be right on. How do I know if they are trustworthy? I’m trying to be conscientious about checking, but this is frustrating, not to mention expensive.

You should discuss this with your diabetes team. They can tell you how best to check accuracy and reliability of each meter. All meters are only plus/minus 10%, and this depends upon how you store your strips, battery strength, keeping the meters clean, how you get a drop of blood, how much you squeeze and other technique issues. With good technique and equipment, you should be in reasonable range.

All the manufacturers also have control solutions available and the best ones have high range and also low range in addition to normal range control solutions for testing purposes. In our clinic, we routinely test all meters at each office visit against the same brand meter since we also want to rely on these meters for accurate blood glucose readings, making insulin dose changes, etc.

SB

[Editor’s comment: When comparing meters, you need to know if the meters are reporting the same thing. Some meters use whole blood glucose values, and others report values as plasma (the difference between the two can approach 20%). Also see How often do you use control solution to check your blood test meter?.

SS]