Glucose Meters - How Accurate Are They?

Nutrition

Glucose Meters - How Accurate Are They?

I test my blood a lot. If I had to put money on it, I believe I average 8-10 finger pricks a day. Even with a continuous glucose monitor (CGM), I double check my levels every time (okay most times) I eat, feel off and/or need to calibrate. However, I find it interesting when I test my glucose seconds apart, my meter doesn't always tell me the exact same readings. 

Admittingly, I do not wash and dry my hands everytime before testing (yes it matters), but even when I am well-groomed in the process, two readings can be 5-15 mg/dl different. Sometimes the difference is even more, and if that is the case, I will test a third time. But which glucose reading do I believe? Often I go with what the second reading is (if I am using the same poked finger) or I do a quick average of the two. Overall, if I test and get a number that doesn't relate to how I am feeling, I test again. 

Besides washing my hands, I try to ensure the test strips are stored in a cool dry place, the lancet is new (I struggle here) and I try to measure my meter's accuracy, comparing it to a lab at my endo appointment, once a year. 

Thankfully, the technology of blood sugar control is getting better and as of 2016 the standards for all new meters were heightened:

  • 95% of all measured blood glucose meter values must be within 15% of the true value,
  • 99% of meter values must be within 20% of the true value,
  • research on new meters must include at least 350 people with diabetes, larger than previously required, and
  • they require greater hypoglycemia (low blood sugar) accuracy than the 2013 ISO standard.

Putting this into practical terms, if the true glucose value is 100 mg/dl, the over the counter meter has to be within 15 mg/dl (85-115 mg/dl) in 95% of cases, and within 20 mg/dl (80-120 mg/dl) in 99% of cases.

For healthcare facilities using glucose meters, a separate guidance has been issued, but with similar standards.

Overall, this is raising the bar to get new, better meters to the market. As of late, my strongest recommendation for clients with diabetes is to move towards the meter from OneDrop. Not only does the meter prove to meet the guidelines, but the price for strips is very economical, and the data transfers automatically to an app where it can be analyzed and shared with a community (if preferred). Please note, I get no kickback from this recommendation, other than providing my clients a tool to better control.

Great things happen when things are accurate and newer meters are another tool to a better A1C%.