Insulin Safety Center

What Else Should I Know?

Unexpected Blood Sugar (Glucose) Readings

If you are getting higher or lower blood sugar results from you glucometer (blood sugar testing device) than expected, there may be other issues. For example, a high reading may be related to a "mishap" with your insulin or the device itself. Below are a few "mishaps" we have learned about that have contributed to unexpected high blood sugar levels.

Digital Numbers and Position of Glucometer Can Result in Inaccurate Readings

A few cases have been reported in which people believed they had high blood sugar levels, even though they did not feel any symptoms. The problem was they were reading the glucose meter upside down. For example, if a glucose meter displays digital numbers, sometimes digits such as six may appear to be a nine when read upside down, and the digit nine may appear to be a six when read upside down. The number 165 can be read upside down as 591, and the number 195 can be read upside down was 561. To avoid this problem, make sure you or any family member (especially for elderly users with poor eyesight) understand where the top and bottom of the glucose reader is.

Certain Drug Products Combined With Certain Blood Glucose Monitoring Strips Can Cause Serious Errors

Some blood glucose monitoring strips use the enzyme glucose dehydrogenase pyrroloquinoline quinone (GDH-PQQ). Test strips using GDH-PQQ technology cannot distinguish between glucose and non-glucose sugars (galactose, maltose, and xylose). Individuals who are receiving products or therapies which contain non-glucose sugars should not use glucometers that use the GDH-PQQ technology. Doing so will result in inaccurate high readings caused by a reaction from these three compounds. If a person with diabetes then takes too much insulin as a result of a falsely elevated reading, it could lead to abnormally low blood sugar (hypoglycemia), coma, or even death.

The products or therapies which may increase non-glucose sugars in the bloodstream are given intravenously (IV) or by a catheter used for peritoneal dialysis. The drugs and therapies available in the United States that cause false readings are listed below:

• Extraneal (icedextrin) peritoneal dialysis solution

• Some immunoglobulins: Octagam 5%, WinRho SDF Liquid, Vaccinia Immune Globulin Intravenous (Human), and HepaGamB

• Orencia (abatacept)

• Adept adhesion reduction solution (4% icodextrin)

• BEXXAR radioimmunotherapy agent

• Any product containing or metabolized into maltose, galactose, or xylose.

If you or a family member have diabetes and receive any of the products listed above, confirm the method used for both the glucose monitor and the test strips you use by reviewing the product information included with the glucose monitor and test strips or contacting the manufacturer of the products.

Heat Exposure

Although most long-term insulin users are aware that heat exposure can effect the stability and potency of insulin, there are circumstances when you may not even be aware that your insulin has been exposed to excessive heat. Additionally, it is important to remember that heat-exposed insulin may not look different. So, if you are experiencing unexpected high blood sugar levels, it is important to consider excessive heat as a contributing factor.

Many reports from consumers show instances where heat was the culprit. For instance, a child removed her insulin cartridge and placed it in a shaded area while swimming. After replacing her pump, she developed severe hyperglycemia despite increasing her insulin dose. Finally, after replacing her insulin cartridge, her blood sugar normalized. The insulin, although not exposed to direct sunlight, became warm enough to cause a significant decrease in potency.

According to Diabetes in Control, a woman discovered her heated waterbed affected her insulin pump. This woman suddenly started experiencing hypoglycemia in the morning, 30 minutes after rising, but before her morning bolus insulin dose before breakfast. Although it was later determined the potency of her insulin was not affected, the heat of the waterbed likely caused an expansion of the tubing causing a bolus of insulin to be administered to her as the tubing cooled. This sudden hypoglycemia resolved when the she switched to a regular mattress.