Consider the following factors that can affect meter accuracy and the steps that can resolve or prevent the problem.
Test strip problems: Throw out damaged or outdated test strips. Store strips in their sealed container; keep them away from heat, moisture and humidity. Be sure the strips are meant for your specific glucose meter.
Extreme temperatures: Keep your glucose meter and test strips at room temperature.
Alcohol, dirt or other substances on your skin: Wash your hands and the testing site with soap and water before pricking your skin. Think about what it would do if you ate an apple and got the juice on your hands but forgot to wash before pricking your finger!
Improper coding: Some meters must be coded to each container of test strips. Be sure the code number in the device matches the code number on the test strip container.
Monitor problems: Fully insert the test strip into the monitor. Replace the monitor batteries as needed.
Not enough blood applied to the test strip: Apply a generous drop of blood to the test strip. Don’t add more blood to the test strip after the first drop is applied.
Testing site location: If you’re using a site other than your fingertip and you think the reading is wrong, test again using blood from a fingertip. Blood samples from alternate sites aren’t as accurate as fingertip samples when your blood sugar level is rising or falling quickly.
If you still have concerns that your meter is working correctly, compare it to another meter. Remember any result within a 20% range is considered acceptable by government standards.