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Objectives:To establish a candidate reference measurement procedure based on isotope dilution liquid chromatography-tandem mass spectrometry (ID-LC-MS/MS) for cyclosporin A, tacrolimus, sirolimus, and everolimus measurements in human whole blood.Methods:The isotope labeled cyclosporine A, tacrolimus, sirolimus, and everolimus were selected as the internal standards. Samples were accurately weighed while protein precipitation and solid phase extraction were selected for the sample preparation. The standard curve method was applied for quantification. The ultra-high liquid chromatography coupled with triple quadrupole mass spectrometer was used for analysis. The specificity, matrix effect, detection limit, quantification limit, precision, accuracy, and uncertainty of the method were evaluated.Results:The method showed good selectivity and specificity. No apparent interferences or matrix effects were found in the target analyte measurements. The detection limits and quantification limits of cyclosporin A, tacrolimus, sirolimus and everolimus met clinical requirements. Intra-batch coefficients of variation ( CV) were from 1.4% to 1.8% for CSA, from 1.7% to 2.8% for TAC, from 1.3% to 3.7% for SRL and from 2.3% to 3.2% for EVR, and total CVs were from 1.8% to 2.9% for CSA, from 1.7% to 3.8% for TAC, from 2.6% to 4.7% for SRL and from 3.5% to 4.6% for EVR. The relative recoveries were from 97.9% to 100.3% for CSA, from 98.4% to 103.1% for TAC, from 99.4% to 102.0% for SRL and from 98.3% to 99.4% for EVR, and the relative expanded uncertainties at four concentrations were from 4.2% to 4.4% for CSA, from 1.5% to 2.4% for TAC, from 4.4% to 4.9% for SRL and from 2.2% to 2.7% for EVR. Conclusion:A candidate reference measurement procedure for the cyclosporine A, tacrolimus, sirolimus, and everolimus in human whole blood was established by ID-LC-MS/MS.
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Objective:To establish the allowable total error (TEa) of the national external quality assessment (EQA) program in line with the current quality level of serum folate measurement in China.Methods:The data of serum total folate test in the clinical laboratory of a hospital in Beijing in 2016 were collected, and the Stata SE 15 software was used for Monte Carlo simulation to obtain the false-negative rate under different bias and inaccuracy conditions. The Origin Pro 9.1 software was used to make the contour figure. The TEa of serum total folate test is derived based on the acceptable false-negative rate. National EQA data of serum total folate in 2020 were collected to calculate the pass rate of participating laboratories and the laboratory pass rate of quality control products at each level under the five TEa derived from the analysis performance on clinical outcomes, biological variation, and the evaluation criterion of national EQA.Results:Based on the influence of analytical performance on clinical outcomes, the TEa was 10%. Under this TEa, the pass rate of the first EQA program of serum total folate in 2020 was more than 80%, and the pass rate of the second time was 73.1%. Under the minimum (46.57%) and appropriate level of TEa (15.52%) derived from biological variation and national EQA evaluation criterion, the pass rate of serum total folate in the two EQA programs in 2020 exceeded 85%.Conclusion:The analytical performance of serum total folate in China cannot meet the requirements of TEa derived based on the effect of analytical performance on clinical outcomes. An appropriate level of TEa derived based on biological variation (15.52%) is suggested as the recommended criterion for the TEa of serum total folate test.
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Background@#Using commutable external quality assessment (EQA) materials is important for monitoring successful harmonization efforts. We assessed the commutability of four human serum pool (HSP) preparations to identify candidate EQA materials for alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activity measurement. @*Methods@#One set each of 85 clinical samples (CSs) was collected for ALT and AST activity measurement. The 15 candidate EQA materials included four types of HSP preparations (A to D): materials A, C, and D contained human original recombinant (HOR) aminotransferases; materials B was mixed leftover samples. The CSs and 15 candidate EQA materials were analyzed using seven routine assays, and the ln-transformed results were analyzed in 21 assay pairs. Commutability was assessed using Deming regression, with a 95% prediction interval (CLSI approach) and the difference in bias with an error component model (International Federation of Clinical Chemistry and Laboratory Medicine [IFCC] approach). @*Results@#For ALT, all materials were commutable for 14–21 assay pairs according to the CLSI and IFCC approaches. For AST, B01-03 showed commutability for 14-21 assay pairs, and C01-03 and D01-03 showed commutability for no less than 10 assay pairs according to the two approaches. A01-06 were commutable for 9-16 assay pairs according to the CLSI approach, but for 6-9 assay pairs according to the IFCC approach. @*Conclusions@#Mixed leftover samples showed desirable commutability characteristics as candidate EQA materials for routine aminotransferase activity measurements. Human serum bases supplemented with HOR were commutable for most routine ALT activity measurements.
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Objective@#The aim of this study is to evaluate the commutability of 16 processed materials for 17-hydroxyprogesterone by using 2 commutability assessment approaches.@*Methods@#52 serum specimens were collected in Clinical Laboratory Department of Beijing Hospital from February 2018 to June 2019. According to the report of the Clinical and Laboratory Standards Institute (EP14-A3) document and the recommendations of the International Federation of Clinical Chemistry and Laboratory Medicine (IFCC) working group on commutabilityassessment, serum 17-hydroxyprogesterone isotope diluent chromatogram tandem mass spectrometry (ID-LC/MS/MS) was used for comparison. Three clinical routine analysis systems (1 radioimmunoassay, 2 LC/MS analysis methods) were used to determine the concentration of 17-hydroxyprogesterone in 52 human serum samples and 16 processed materialsfor commutabilityassessment.@*Results@#Combined with the results of the two commutability assessment, all accuracy verification materials and national steroid hormone standards showed good commutability in the LC/MS analysis system, and 6/9 EQA materials showed commutability in the three routine analysis systems.All materials showed good commutability in the LC/MS analysis system of bias difference method.@*Conclusions@#The two kinds of commutability assessment results are different. Bias difference method has more clinical value, but it has certain application limitations. The use of fresh frozen human serum as a quality assessment materialfor serum 17-hydroxyprogesterone is meets the commutability requirement.
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Objective:To establish an accurate quantitative method for the determination of serum glycated albumin (GA) based on isotope dilution liquid chromatography tandem mass spectrometry (ID-LC/MS/MS).Methods:This study optimized the ID-LC/MS method recommended by the Japan Society of Clinical Chemistry (JSCC). Albumin (Alb) was purified by anion exchange chromatography. The standard solution of purified sample, lysine (Lys) and deoxyfructosyl lysine (DOF-Lys) and their mixed internal standard were weighed accurately by weight method. The Alb was hydrolyzed to amino acid, and Lys and DOF-Lys were detected to determine GA. The method was evaluated and compared with the routine method.Results:The purity of Alb was 100%. The R 2 ranges of Lys and DOF-Lys linear standard curves were 0.997 8-0.999 9 and 0.999 4-1.000 0. The results of three-day precision evaluation of low, medium and high concentrations of serum were 0.69%-1.97%, 1.13%-2.33% and 1.37%-2.54% in intra, inter and total Coefficient of variation ( CV). In the accuracy evaluation, the deviations between the results of three concentration standards and the certified value were -2.56%, -1.87% and-2.94%. The matrix effects of Lys and DOF-Lys were 89.92% and 109.98%, and the carryover rates were -1.13% and -3.27% respectively. The detection limit and quantitative limit of Lys were 0.075 nmol/g and 0.248 nmol/g, and the DOF-Lys were 0.007 nmol/g and 0.024 nmol/g. The relative expanded uncertainty was 1.60%-2.03%. The fitting regression curve R 2 with the routine method was 0.970 7. Conclusions:A method was established for the detection of serum GA. The method evaluation was accurate and reliable. It was expected to be a candidate reference method for the detection of serum GA.
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Objective:The aim of this study is to evaluate the commutability of 16 processed materials for 17-hydroxyprogesterone by using 2 commutability assessment approaches.Methods:52 serum specimens were collected in Clinical Laboratory Department of Beijing Hospital from February 2018 to June 2019. According to the report of the Clinical and Laboratory Standards Institute (EP14-A3) document and the recommendations of the International Federation of Clinical Chemistry and Laboratory Medicine (IFCC) working group on commutabilityassessment, serum 17-hydroxyprogesterone isotope diluent chromatogram tandem mass spectrometry (ID-LC/MS/MS) was used for comparison. Three clinical routine analysis systems (1 radioimmunoassay, 2 LC/MS analysis methods) were used to determine the concentration of 17-hydroxyprogesterone in 52 human serum samples and 16 processed materialsfor commutabilityassessment.Results:Combined with the results of the two commutability assessment, all accuracy verification materials and national steroid hormone standards showed good commutability in the LC/MS analysis system, and 6/9 EQA materials showed commutability in the three routine analysis systems.All materials showed good commutability in the LC/MS analysis system of bias difference method.Conclusions:The two kinds of commutability assessment results are different. Bias difference method has more clinical value, but it has certain application limitations. The use of fresh frozen human serum as a quality assessment materialfor serum 17-hydroxyprogesterone is meets the commutability requirement.