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Medical Devices

FDA Reminders For Falsely Elevated Glucose Readings From Use of Inappropriate Test Method

Intended Audience

All personnel performing glucose monitoring

This is to remind you of the potential for death or serious injury from treatment based on falsely elevated glucose readings from a glucose dehydrogenase-based test method that is used to monitor diabetic patients receiving parenteral drug products containing maltose or galactose, or oral xylose. Recommendations for avoiding this problem are provided below.

What’s the problem?

We recently received a report of a patient who suffered irreversible brain damage following an aggressive insulin treatment that was given for elevated glucose readings. Unfortunately, the elevated glucose readings were incorrect because the glucose monitoring device, which was unable to distinguish between glucose and maltose, was reacting to the maltose in the intravenous immunoglobulin solution that the patient was receiving.

Serious injuries and deaths from these false glucose readings continue to occur despite this problem being discussed widely in the literature and identified in the Clinical Laboratories Standards Institute document titled, Glucose Monitoring in Settings Without Laboratory Support; Approved Guideline (AST 4-A2).

What are the different glucose test methods?

Self-monitoring glucose devices used by diabetics at home and in point-of-care settings, and laboratory glucose assays all use one of the following test methods: glucose dehydrogenase pyrroloquinolinequinone (GDH- PQQ), glucose dehydrogenase nicotinamide adenine dinucleotide (GDH-NAD), glucose oxidase, or glucose hexokinase. The test method is clearly marked in the device labeling/operator’s manual.

The glucose monitoring systems that use the GDH-PQQ method cannot distinguish the sugars glucose, maltose, galactose or xylose from each other. The GDH-PQQ method may provide higher readings in the presence of any of these sugars.

Glucose monitoring systems that use GDH-NAD, glucose oxidase, or glucose hexokinase methods are not affected by the presence of maltose, galactose or xylose.

What kinds of medical products may induce the falsely high readings?

Medical products such as intravenous immunoglobulin solutions, oral xylose, and peritoneal dialysis solutions may contain or be metabolized to maltose, galactose or xylose.


To help prevent false glucose readings due to the limitations of the glucose monitoring systems, personnel performing glucose monitoring should:

  1. Know whether their glucose testing method uses GDH-PQQ, GDH-NAD, glucose oxidase, or glucose hexokinase to measure the sugar level. (The testing method is specified in the device operating manual and is obtainable from the device manufacturer.)
  1. Use only GDH-NAD, glucose oxidase or glucose hexokinase methods if the patient has received intravenous immunoglobulin solutions within the last 24 hours, taken oral xylose within the last 24 hours, or is on peritoneal dialysis.

Reporting to FDA

If you suspect that a death or serious injury was related to false glucose readings, you should follow the mandatory reporting procedure established by your hospital or user facility.

For events that did not result in death or serious injuries, you can report directly to the device manufacturer or to MedWatch, the FDA’s voluntary reporting program. MedWatch can be contacted by phone at 1-800-FDA-1088; by FAX at 1-800-FDA-0178; by mail to MedWatch, Food and Drug Administration, 5600 Fishers Lane, Rockville, MD 20852-9787; or online at

Page Last Updated: 08/05/2015
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