Trueness evaluation of 13 routine measurement systems for glucose

Objective To evaluate the trueness of 13 routine measurement systems for glucose and the role of standard reference materials in improving harmonization and trueness among routine measurement systems. Methods The research is related to the reagent evaluation.The isotope dilution liquid chromatography tandem mass spectrometry (ID-LC/MS/MS) method was applied as the comparative method.13 routine measurement systems,composed of 13 kits and calibrator for glucose measurement (GOD method and/or HK method) from Roche, Biosino, Mindray, Kehua, Maker, Fenghui, Wako companies and Hitachi 7170A automatic analyzer,were chosen as the test methods.The comparative method and test methods were applied to 20 fresh frozen sera collected from outpatient of diabetes of Beijing hospital in 2011 and two levels of NIST SRM 965a for glucose concentration.Linear regression analysis was made for the results of comparative methods and every test method to estimate the predicted bias at given medical decision levels.The mathematics relationship between the assigned values of SRM965a and results from each test method was used to recalibrate the results of 20 fresh frozen sera from 13 test methods.CV,average bias and predicted bias were compared before and after recalibration. Results All test methods demonstrated good precision (CV 0.998,all P<0.01) with comparative method when measuring 20 fresh frozen sera in glucose results.The bias ranged from -0.11 to 0.27 mmol/L when 20 fresh frozen sera measured by 13 test methods.The predicted bias ranged from -0.08 to 0.23 (-1.43% to 4.11%),-0.10 to 0.26 mmol/L (-1.43% to 3.71%) and -0.18 to 0.37 mmol/L (-1.62% to 3.33%) at the given medical decision levels of 5.6,7.0 and 11.1 mmol/L respectively.After recalibration,the average of between-method CV s measured by 13 test methods decreased from 2.11% (1.55% to 2.39%) to 1.34% (0.95% to 1.82%).The average of relative bias increased from 1.11% (1.72% to 4.85%) to -2.52% (-5.12% to 1.32%). Conclusions All test methods demonstrated good trueness and their calibration traceability was verified.Recalibration of routine systems by Standard Reference Materials contributes to the harmonization among methods.(Chin J Lab Med,2013,36:523-528) Key words: Blood glucose; Reference values; Diagnostic tests; routine; Calibration; Reagent kits; diagnostic; Bias (epidemiology)