BMJ Case Reports 2017; doi:10.1136/bcr-2017-219928
  • Reminder of important clinical lesson

Erroneously elevated glucose values due to maltose interference in mutant glucose dehydrogenase pyrroloquinolinequinone (mutant GDH-PQQ) based glucometer

  1. Subhankar Chowdhury2
  1. 1Department of Medicine, Midnapore Medical College and Hospital, Midnapore, India
  2. 2Department of Endocrinology and Metabolism, IPGMER/SSKM Hospital, Kolkata, India
  1. Correspondence to Dr Partha Pratim Chakraborty, docparthapc{at}
  • Accepted 25 April 2017
  • Published 12 May 2017


Currently available glucose test strip enzymes include glucose oxidase (GOD) and glucose dehydrogenase (GDH). In GDH-based glucometers, glucose oxidation can be catalysed by different cofactors: nicotinamide adenine dinucleotide (GDH-NAD), flavin adenine dinucleotide (GDH-FAD), pyrroloquinolinequinone (GDH-PQQ) and mutant GDH-PQQ. GOD-based and GDH-NAD-based glucometers are substrate-specific and do not react with sugars other than glucose. GDH-FAD reacts with xylose only in addition to glucose. GDH-PQQ is not glucose-specific; in addition to glucose, it reacts with different other sugars and produces falsely high values of capillary glucose in the presence of such substances. There are reports of several deaths associated with usage of GDH-PQQ-based test strips. A modified form of GDH-PQQ, the so-called mutant GDH-PQQ, is supposedly free from such interferences. In this article spuriously high glucose values due to maltose interference in a glucometer using the mutant GDH-PQQ chemistry are being reported.


  • Contributors PPC and SP were involved in managing the patient, literature search and preparing the manuscript. RB and SC were involved in literature search, preparing the manuscript and providing intellectual inputs.

  • Competing interests None declared.

  • Patient consent Obtained.

  • Provenance and peer review Not commissioned; externally peer reviewed.

Responses to this article

Register for free content

The full text of all Editor's Choice articles and summaries of every article are free without registration

The full text of Images in ... articles are free to registered users

Only fellows can access the full text of case reports (apart from Editor's Choice) - become a fellow today, or encourage your institution to, so that together we can grow and develop this resource

Don't forget to sign up for content alerts so you keep up to date with all the case reports as they are published, and let us know what you think by commenting on the Editor's blog

Navigate This Article