title: Application of Sigma Metrics and Performance Comparison Between Two Biochemistry Analyser and a Blood Gas Analyser for the Determination of Electrolytes.
abstract: BACKGROUND
  Electrolytes have a narrow range of biological variation and small changes are clinically significant. It is important to select the best method for clinical decision making and patient monitoring in the emergency room. The sigma metrics model provides an objective method to evaluate the performance of a method.
  
  
  OBJECTIVE
  To calculate sigma metrics for electrolytes measured with one arterial blood gas analyser including two auto-analysers that use different technologies. To identify the best approach for electrolyte monitoring in an emergency setting and the context of routine emergency room workflow.
  
  
  METHODS
  The Coefficient of Variation (CV) was determined from Internal Quality Control (IQC). Data was measured from July 2015 to January 2016 for all three analysers. The records of KBUD external quality data (Association of Clinical Biochemists, Istanbul, Turkey) for both Mindray BS-2000M analyser (Mindray, Shenzhen, China) and Architect C16000 (Abbott Diagnostics, Abbott Park, IL) and MLE clinical laboratory evaluation program (Washington, DC, USA) for Radiometer ABL 700 (Radiometer Trading, Copenhagen, Denmark) during the study period were used to determine the bias.
  
  
  RESULTS
  The calculated average sigma values for sodium (-1.1), potassium (3.3), and chloride (0.06) were with the Radiometer ABL700. All calculated sigma values were better than the auto-analysers.
  
  
  CONCLUSIONS
  The sigma values obtained from all analysers suggest that running more controls and increasing the calibration frequency for electrolytes is necessary for quality assurance.
authors.affiliation: Department of Clinical Biochemistry, Saglik Bilimleri University, Bursa Yuksek Ihtisas Training and Research Hospital , Bursa, Turkey .
authors.forename: Yasemin
authors.initials: Y
authors.lastname: Ustundag-Budak
authors.affiliation: Department of Clinical Biochemistry, Saglik Bilimleri University , Bursa Yuksek Ihtisas Training and Research Hospital, Bursa, Turkey .
authors.forename: Kagan
authors.initials: K
authors.lastname: Huysal
keywords: Chloride; Potassium; Quality control; Quality improvement; Sodium