The Impact of Human Error on Meter Accuracy

Many individuals with type 2 diabetes monitor their day-to-day diabetes control with the help of a blood glucose meter. Blood glucose monitoring is typically recommended for those who have insulin treated diabetes. However, blood glucose monitoring may also be recommended for those managing their diabetes with oral medications and/or lifestyle changes (i.e. diet and exercise). As stated by the American Association of Diabetes Educators, “Self- monitoring of blood glucose (SMBG) provides feedback on the effectiveness of the treatment plan…”¹

A diabetes educator can play an important role in helping with meter selection as well as teaching proper blood glucose monitoring technique. According to a recent article from the Journal of Diabetes Science and Technology, “Inappropriate handing of SMBG (i.e. human error) has been identified as the most common factor affecting BG (blood glucose) results; more than 90% of overall inaccuracies result from incorrect use of BG meters."²

Over-the-counter blood glucose meters are regulated by the Food and Drug Administration (FDA) and are required to meet strict accuracy criteria. The most recent accuracy standards (as of 2013) are as follows:

• “95% of all measured blood glucose meter values must be within 15% of the true value (a lab measurement)
• 99% of meter values must be within 20% of the true value.”³

However, there is a greater risk of both improper storage and handling of blood glucose meters and test strips when used for personal use in comparison to use in a professional setting thus potentially having a negative impact on the above stated accuracy standards.

Human error responsible for inaccurate blood glucose results

The following is a list of “Human Errors” that can result in inaccurate blood glucose results:

• Contaminated blood sample due to not cleaning hands properly
  • Wash hands with soap and water before checking blood glucose
  • If no soap or water is available, use alcohol or hand sanitizer
  • Make sure hands are completely dry before testing
  • If none of above are available, use the second drop of blood, which is less likely to be contaminated than the first drop. Apply the second drop of blood to test strip after first drop of blood has been wiped away.^4,5
• Not applying enough blood to test strip
  • Many meters now use test strips that have “second chance sampling” that allow the user to apply additional blood (usually within 60 seconds of the initial sample).
• Using expired test strips
  • Expiration date can be found on test strip container
• Improper storage of test strips
  • Keep test strips in container until ready to use and avoid exposure to temperature extremes and moisture.
• Applying blood to test strip before test strip is placed into meter
• Using test strips that are not compatible with the meter you are using
  • Compatible test strips are usually found on the meter box, user guide, and/or meter website
• Squeezing your finger to get a sufficient blood drop may result in unreliable blood glucose readings.^4,5
  • To help ensure an adequate blood drop wash hands with warm water or hang you hand at your side for a few seconds (before finger poke). Both options can help improve blood flow to finger tips.
• Using a blood sample from an alternate test site not been approved by the manufacturer of the meter.
• Misreading meter results
  • Choose meter with a large color screen and large text (this may only be necessary for those who are visually impaired)
• Improper storage and/or handling of meter
  • Avoid exposing meter to temperature extremes
  • Some meters may also be impacted by changing altitudes
• Using an old meter
  • The average life of a meter is 3 to 5 years