Practice Lesson of the Week

Falsely elevated capillary glucose and ketone levels and use of skin lightening creams

BMJ 2015; 351 doi: https://doi.org/10.1136/bmj.h3879 (Published 29 July 2015) Cite this as: BMJ 2015;351:h3879
  1. Clara H Bouché, consultant physician1,
  2. Jean-Pierre Garnier, senior lecturer2,
  3. Siméon-Pierre Choukem, clinical and research fellow1,
  4. Jean-François Gautier, professor and consultant physician1
  1. 1Department of Diabetes and Endocrinology, Assistance Publique - Hôpitaux de Paris, DHU FIRE, Lariboisière Hospital University Paris-Diderot Paris-7, 75010 Paris, France, and INSERM UMRS 1138, Cordeliers Research Centre, 75006, Paris, France
  2. 2Biochemistry Laboratory, Saint-Louis University Hospital, Assistance Publique - Hôpitaux de Paris, University Paris Descartes, 75010 Paris, France
  1. Correspondence to: Jean-François Gautier jean-francois.gautier{at}lrb.aphp.fr
  • Accepted 3 June 2015

Hand washing before glucose and ketone fingerprick testing prevents false results in users of skin lightening cosmetics

Hyperglycaemia associated with ketosis reflects severe insulin deficiency that mandates immediate insulin therapy. Point-of-care devices to measure capillary glucose have become essential in diabetes management.1 Management of hyperglycaemic crisis has also been improved by the measurement of β-hydroxybutyrate in a fingerprick blood specimen. The method is quick, accurate, and reliable,2 3 4 and recommended to medical care providers and patients.2 5 6 Here we report two cases of misleadingly high capillary glucose and ketone measurements that could have been prevented by careful hand washing. We also identify the chemical compound, hydroquinone, that interferes with capillary results.

Case reports

Case 1

A 37 year old sub-Saharan African woman with a history of insulin treated diabetes was admitted to hospital for poor glycaemic control. Despite correct adjustment of insulin doses, capillary glucose and ketone levels rose unpredictably from 5.4 to 25 mmol/L glucose and from 0 to “HI” (above higher interpretation limit, that is, >8 mmol/L ketone) within 48 hours. Meanwhile, urinary and plasma ketone determinations were negative. We therefore suspected a false ketonaemia induced by hand cream application, and this was confirmed by the disappearance of capillary ketone (0.2 mmol/L) and a …

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