title: Point-of-care glucose testing: effects of critical care variables, influence of reference instruments, and a modular glucose meter design.
abstract: OBJECTIVE
  To assess the clinical performance of glucose meter systems when used with critically ill patients.
  
  
  METHODS
  Two glucose meter systems (SureStepPro and Precision G) and a modular adaptation (Immediate Response Mobile Analysis-SureStepPro) were assessed clinically using arterial samples from critically ill patients. A biosensor-based analyzer (YSI 2700) and a hospital chemistry analyzer (Synchron CX-7) were the primary and secondary reference instruments, respectively.
  
  
  METHODS
  Two hundred forty-seven critical care patients at the University of California, Davis, Medical Center participated in this study.
  
  
  METHODS
  Error tolerances of +/-15 mg/dL for glucose levels </=100 mg/dL and +/-15% for glucose levels >100 mg/dL were used to evaluate glucose meter performance; 95% of glucose meter measurements should fall within these tolerances.
  
  
  RESULTS
  Compared to the primary reference method, 98% to 100% of SureStepPro and 91% to 95% of Precision G measurements fell within the error tolerances. Paired differences of glucose measurements versus critical care variables (Po(2), pH, Pco(2), and hematocrit) were analyzed to determine the effects of these variables on meter measurements. Po(2) and Pco(2) decreased Precision G and SureStepPro measurements, respectively, but not enough to be clinically significant based on the error tolerance criteria. Hematocrit levels affected glucose measurements on both meter systems. Modular adaptation did not affect test strip performance.
  
  
  CONCLUSIONS
  Glucose meter measurements correlated best with primary reference instrument measurements. Overall, both glucose meter systems showed acceptable performance for point-of-care testing. However, the effects of some critical care variables, especially low and high hematocrit values, could cause overestimated or underestimated glucose measurements.
authors.affiliation: Department of Medical Pathology, University of California, Davis, USA.
authors.forename: R F
authors.initials: RF
authors.lastname: Louie
authors.forename: Z
authors.initials: Z
authors.lastname: Tang
authors.forename: D V
authors.initials: DV
authors.lastname: Sutton
authors.forename: J H
authors.initials: JH
authors.lastname: Lee
authors.forename: G J
authors.initials: GJ
authors.lastname: Kost
mesh_terms: D001786:Blood Glucose / Q000032:analysis*; D015190:Blood Glucose Self-Monitoring / Q000295:instrumentation*; D002245:Carbon Dioxide / Q000097:blood; D003422:Critical Care / Q000379:methods*; D004867:Equipment Design; D006400:Hematocrit; D006801:Humans; D006863:Hydrogen-Ion Concentration; D010100:Oxygen / Q000097:blood; D019095:Point-of-Care Systems; D011934:Reagent Strips; D012016:Reference Values; D015203:Reproducibility of Results
chemical_list: D001786:Blood Glucose; D011934:Reagent Strips; D002245:Carbon Dioxide; D010100:Oxygen