How accurately do we measure blood glucose levels in intensive care unit (ICU) patients?

Hyperglycaemia is commonly found in critically ill patients as a result of numerous processes such as increased gluconeogenesis and glycogenolysis caused by elevated levels of corresponding hormones and insulin resistance. As the clinical consequence of hyperglycaemia has been shown to increase morbidity and mortality in various clinical settings, many hospitals by now use tight glycaemic control protocols for their patients in intensive care units to maintain normoglycaemia. The success of the intensive insulin therapy depends crucially on frequent and accurate blood glucose measurements with immediate feedback of results. Therefore, in almost all cases, this will be done by point-of-care testing methods, raising the question of how accurately blood glucose levels are actually measured and what devices should be used. This review focusses on glucose assay principles, specimen matrices, influences and interferences of glucose measurements and finally looks at the numerous evaluation reports on point-of-care glucose testing devices.