title: Analytical validation of microdialysis analyzer for monitoring glucose, lactate and pyruvate in cerebral microdialysates.
abstract: BACKGROUND
  Cerebral microdialysis is a valuable tool for neurochemical monitoring of acute brain injury. We performed an independent analytical validation of glucose, lactate and pyruvate methods on the new ISCUS(flex) new analyzer developed by CMA Microdialysis.
  
  
  METHODS
  Evaluation of analytical parameters included limit of detection, limit of quantification, linearity, intra- and inter-assay imprecision expressed as the coefficient of variation (CV), recovery, inter-sample and inter-reagent contamination, drug and bilirubin interferences, sample stability, method comparison.
  
  
  RESULTS
  Linearity ranges were 0.1-25 mmol/L, 0.2-12 mmol/L and 19-1500 μmol/L for glucose, lactate and pyruvate respectively. For critical threshold, intra- and inter-assay CVs were 3.1/4.5% for glucose (1 mmol/L), 3.5/4% for lactate (4 mmol/L) and 3.3/4.3% for pyruvate (100 μmol/L). Inter-assay CVs for lactate/pyruvate (LPR) and lactate/glucose (LGR) ratios were 5.9% and 6.0% respectively. For glucose, lactate, pyruvate, LPR and LGR, the reference change values (RCV) were 20%, 26%, 20%, 27% and 28% respectively. Practically, variations below 27% between two successive LPR values could not be interpreted as significant.
  
  
  CONCLUSIONS
  These data prove that ISCUS(flex) has the qualities required for clinical application in neuro-intensive care. Correct clinical interpretation of data need the implementation of a strict quality control program and strong cooperation between clinicians and biologists.
authors.affiliation: HCL, Centre de Biologie et de Pathologie Est, Laboratoire de Neurobiologie, Lyon, France. yannick.tholance@chu-lyon.fr
authors.forename: Yannick
authors.initials: Y
authors.lastname: Tholance
authors.forename: Gleicy
authors.initials: G
authors.lastname: Barcelos
authors.forename: Isabelle
authors.initials: I
authors.lastname: Quadrio
authors.forename: Bernard
authors.initials: B
authors.lastname: Renaud
authors.forename: Frederic
authors.initials: F
authors.lastname: Dailler
authors.forename: Armand
authors.initials: A
authors.lastname: Perret-Liaudet
mesh_terms: D001921:Brain / Q000378:metabolism*; D005947:Glucose / Q000032:analysis*; D006801:Humans; D019344:Lactic Acid / Q000032:analysis*; D057230:Limit of Detection; D017551:Microdialysis / Q000295:instrumentation*; D019289:Pyruvic Acid / Q000032:analysis*; D015203:Reproducibility of Results
chemical_list: D019344:Lactic Acid; D019289:Pyruvic Acid; D005947:Glucose