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Objective To evaluate the performance of Cys C results among two detection system.Methods The particle-enhanced immunonephrometic assay was used in Dade Behring BNII. Immunoturbic assay was used in Hitachi 7170 to evaluate the JING' YUAN reagents.We compared the precison,linearity,interference,correlation,and calibrators agreement with Dade Behring BNII.Results The total CV of the samples that contain 0.6-5.0 mg/L was less than 10%.The Dade Behring and JING'YUAN method showed good linearity.Haemoglobin(10 g/L),Bilirubin(300 mg/L), Vitamin C(5 g/L)in the tested sample had no significant interference in the assay(interference 0.05) between JING' YUAN and Dade Behring reagents.Values were slightly lower than that from the Dade Behring BNII method,the mean bias was-0.16.The bias range was 1.1%-23% between JING'YUAN and Dade Behring for one sample.Conclusions The precision,linearity and interference test were suitable for routine Cys C measurement on automated biochemistry analyzer,but results has bias.
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Objective To evaluate the value of serum creatinine(Scr),creatinine clearance (Ccr),MDRD equation 7(MDRD 7),~(99)Tc~m-DTPA renal dynamic imaging(gGFR)and cystatin C in screening changed glomerular filtration function in type 2 diabetic patients.Methods The ~(99)Tc~m-Diethylene Triamine Pentaacetic Acid(~(99)Tc~m-DTPA)plasma clearance(rGFR)obtained with the dual plasma sampling method was used as a reference with which Scr,Ccr,MDRD 7,gGFR and Cystatin C were compared.Results Sixty of type 2 diabetic patients were selected,including 35 male and 25 female.The average age was(62.4?11.7)years and the average diabetic history was(10.66?9.35)years.Scr,Ccr, MDRD 7,gGFR were all correlated significantly with rGFR.Correlation coefficients were 0.675 for Ccr, -0.588 for Cystatin C,-0.500 for Scr,O.428 for MDRD 7,0.367 for gGFR(P values all
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Objective To compare the coherence of serum creatinine,creatinine clearance(Ccr), Cystatin C,and estimated glomerular filtration rate(eGFR)in each stage of chronic kidney disease(CKD) patients.Methods Creatinine in serum and urine were determined by Jaffe method;serum Cystatin C was measured by particle enhanced turbidimetric method,while eGFR was calculated using the abbreviated Modification of Diet in Renal Disease(MDRD)equation which was mainly based on the serum creatinine concentration.According to the American national kidney foundation-Kidney Disease Outcome Quality Initiative(NKF-K/DOQI)guideline,all cases were grouped by eGFR into 5 stages.Results In these 228 cases,as eGFR decreased gradually,the average levels of creatinine and Cystatin C increased,while Ccr decreased.The level of each items showed a statistic difference among each stage(P0.05);in eGFR 60-89 ml/min group,the average level of creatinine was 83.3 ?mol/L,the abnormal rate was only 6.8%,it was not a sensitive marker to detect the slightly damaged GFR,the levels of Ccr and Cystatin C showed a marginal decrease and increase,with an abnormal rates of 70% and 86%,there was a statistic difference among the three abnormal rates(P
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Objective To investigate the efficacy of using a calibrator with values assigned with the reference method for improving the comparability of serum gamma-glutamyltransferase (GGT) measurements.Methods The IFCC reference method for GGT was established and the performance was verified by testing a certified reference material (CRM).A calibrator was prepared and its value for GGT was assigned with the reference method.Forty serum samples were measured on different (including HITACHI 7600,7060,7170,7180 and BECKMAN LX20,OLYMPUS AU 400) chemistry analyzers with Zhongsheng GGT reagent kits calibrated with the calibrator.The samples were also measured on the same analyzers using a theoretical factor.Biases of results obtained with the calibration and with the theoretical factor based calculation were compared.Results The reference method resuhs on the CRM agreed the certified value within the stated uncertainty.Serum results calculated from the theoretical factor showed various biases and inter-analyzer variations.When the analyzers were calibrated with the calibrator,the number of results with biases less than 10% became significantly higher and those with biases more than 20% significantly lower.The variation of the results on 5 serum samples was reduced from 11.0%～14.0% to less than 5% by using the calibrator.Conclusion Accuracy and comparability of GGT measurements with of ZhongSheng GGT kits can be improved by using a calibrator that has a value assigned with the reference method.
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Objective To investigate the accuracy and comparability of ?-glutamyltransferase (?- GT) measurement results on human serum samples and controI materials before and after calibration with a common human serum calibrator.Methods A human serum calibrator was prepared by pooling fresh serum aliquots and assigning a value for ?-GT with the IFCC reference method.The calibrator together with 5 human serum samples and 10 control samples were sent to 15 clinical laboratories and the sermn and control samples were measured with different analytical systems before and after a calibration with the calibrator.The results were analyzed for biases and interlaboratory variations.Results For the serum samples,the calibration resulted in reductions in biases from -9.0%～-14.2% to -0.8%～-7.9%,and in interlaboratory variations from 6.9%～11.6% to 2.8%～4.4%.No improvement was observed on the control samples.Conclusions Accuracy and comparability of serum ?-GT measurements can be improved by using a common human serum calibrator.Some control materials may not be commutable for human serum in ?-GT measurements.