Clinical Case Study

Diabetic hypoglycemia: a case of different capillary blood glucose readings from two identical glucose meters

Dr. Alex J Graveling MRCP, Department of Diabetes, Royal Infirmary of Edinburgh, Edinburgh, UK

Diabetic Hypoglycemia Oct 2010, Volume 3, Issue 2: page 18-19

Abstract

A 61-year old male with a 54-year history of type 1 diabetes, hypertension and ischemic heart disease became drowsy while attending the hospital diabetes outpatient department. Capillary blood glucose was measured at 3.8 mmol/l and he was treated for presumed hyopglycemia with a glucose drink followed by intravenous dextrose; 25 minutes later, a different glucose meter was used to record a capillary blood glucose value of 7.8 mmol/l. Because recovery was slow, the patient was transferred to the Emergency Department.  A laboratory blood glucose result from a sample taken 5 minutes before the second glucose meter measurement reported levels of 2.5 mmol/l. This case illustrates how two blood glucose meters of the same make and model can give significantly different results; other sources of diagnostic inaccuracy are discussed. Clinical suspicion of hypoglycemia requires prompt treatment whether or not capillary blood glucose can be measured immediately. When possible, confirmatory laboratory measurement of venous blood glucose should be obtained in cases of suspected severe hypoglycemia.

Keywords: hypoglycemia, type 1 diabetes, glucose meter, capillary glucose reading