Inspiration And Expert Advice: Expert Columns
A Tale of Two Glucose Monitors: Which One is Telling the Truth? (continued)
Consider that in 1993, the American Diabetes Association recommended a target meter accuracy goal of +/- 5%. No meter manufacturers have been able to develop a cost-effective system to meet that goal. An international standard is currently under development that recommends meter accuracy of +/- 20 mg/dl for glucose values under 100 mg/dl and +/- 20% for higher glucose values.
What do I do with the 17-point difference?
What was your glucose result that yeilded a 17-point difference? For example, if you had a 200 glucose plus or minus 20 percent, an acceptable variance range would be 160-240 (if you did a simultaneous test on a same-model meter). May seem like a wide range of numbers. That’s why is it imperative to use the same meter model to minimize variables, and to look at trends and patterns of glucose over time.
Meters have a range of accuracy, as glucose is variable. It’s our best science, and sure beats peeing on a glucose test strip (as was common pre-80s, and it was no where near the accuracy of blood glucose monitoring).
Besides quality control, how can I check meter accuracy?
Check your meter against a venipuncture glucose test. The next time you go in for lab work that includes a glucose level, explain to the phlebotomist that you need a drop of blood that they drew from your arm. Ask them to put the drop of blood on your test strip so you can run a glucose on your home meter. If they give you a hard time, just use your own lancet to run a glucose on your home glucose monitor. The key here is, you need to do it at the same time. If you have your lab drawn at 7 a.m., then you drive home and poke your finger at 7:45 a.m., you cannot compare the two readings.
Your glucose reading should be within 10-15 percent of the venipuncture result.
What else can interfere with home glucose monitor results?
A variety of factors can affect the accuracy. These include cleanliness of hands, wet hands (may have a higher than expected result), humidity in the bathroom (if that’s where you store your strips), whether or not the meter is coded correctly, expired or third-party test strips, oversqueezing the finger to get a sample, and alternate site testing (glucose values taken from forearms typically respond slower than fingersticks – you might have a 70 from the finger and a 90 from the forearm).
Many manufacturers systems have built-in safety mechanisms to eliminate these issues (like automatic underfill detection, temperature control, no calibration or coding needed).
The key to use the same model of meter (i.e. use a couple of Freestyle Lites), and look at trends. Just like the economy, we don’t panic with one number or report—it’s the collective reports that paint a complete picture.
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NOTE: The information is not intended to be a replacement or substitute for consultation with a qualified medical professional or for professional medical advice related to diabetes or another medical condition. Please contact your physician or medical professional with any questions and concerns about your medical condition.
