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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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Aldosterone and renin are important clinical indicators in the diagnosis and treatment of hypertension. There are two kinds of methods for aldosterone detection, including immunoassay and mass spectrometry. The coefficients of variation within the methods, as well as the deviation between methods are large.And the results of immunoassay are much higher than that of mass spectrometry. Clinically, renin tests mainly include renin concentration and renin activity, both of which have advantages and disadvantages in the diagnosis and treatment of hypertension. The disordered test results of aldosterone and renin brings great trouble to the clinical diagnosis and treatment. Standardization/consistency is urgently needed to make the test results of each laboratory more accurate and comparable. The standardization project for renin and aldosterone in China will greatly promote the standardization process in order to provide accurate and comparable clinical tests.
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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 propose and validate a reduced volume β-quantification method to measure serum high-density lipoprotein cholesterol (HDL-C) and low-density lipoprotein cholesterol (LDL-C). Methods The reduced volume β-quantification method involved separation of LDL and HDL by ultracentrifugation and preparation of HDL by chemical precipitation. The sampling and reconstitution of the bottom fractions were performed gravimetrically and sample volume was thus decreased from 5 to 0.8 ml. High performance liquid chromatography was used to determine the cholesterol concentration of bottom fractions and HDL-C in the supernatant. Serum levels of LDL-C depended on a calculation of bottom fractions cholesterol minus HDL-C. Results The total CVs for HDL-C and LDL-C were 0.65％ -1.75％ and 0.63％ -1.11％. The results of the developed method were consistent with the current reference method and well within the allowable bias for Cholesterol Reference Method Laboratory Network surveys. Conclusion A new method for the measurement of HDL-C and LDL-C has been established. This method requires a small amount of serum and is easy to operate, exhibiting a desirable precision and accuracy. It is reliable and can be used as a candidate reference method for HDL-C and LDL-C.
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Decreased serum high-density lipoprotein cholesterol (HDL-C) and increased low-density lipoprotein cholesterol (HDL-C) concentrations are important risk factors for cardiovascular diseases. Achieving accurate and comparable HDL-C and LDL-C results is the primary requirement for the prevention and treatment of cardiovascular diseases, in which reference system including reference method, reference materials and standardization programs are needed. The current reference method for HDL-C and LDL-C measurement is the β-quantification method developed by the United States Center for Disease Control and Prevention (CDC), a multi-step procedure involving ultracentrifugation, chemical precipitation, and cholesterol analysis by CDC reference method. This method uses a large amount of serum and is technically demanding which limited its application in standardization. The reduced volume β-quantification method uses a small volume of serum sample, is simple and high through put and is more applicable. However, both methods are sensitive to serum matrix. Commutability of reference materials should be evaluated when they are used to calibrate routine methods. Fresh (non-frozen) serum samples should be used for a split sample comparison between reference and direct methods. In addition, development of reference measurement procedure based on ultracentrifugation and preparation of commutable reference materials are the important work in lipoprotein standardization.
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Objective To evaluate the comparability and consistency of two kinds of triglycerides reference methods, one of which is the isotope dilution liquid chromatography-mass spectrometry (LC/MS) in the Cholesterol Reference Method Laboratory Network (CRMLN), the other isthehigh-performance liquid chromatography (HPLC) method for triglyceride detection in China. Methods 52 fresh frozen sera with triglycerides levels among 0.45-4.52 mmol/L were determined by LC/MS and HPLC. After evaluation the precision and accuracy of the two methods,a series of analyses were conducted including plotting to scatter plots and deviation graphs, testing outliers, selecting the best fitting regression models and calculating the regression equations and parameters, and so on. The expected deviation at the level of medical decision of triglycerides and the 95％confidence range were statistically analyzed.Results For HPLC method, the CV of instrument measurement was 0.29％(0％-1.16％), the total CV of samples measurement was 0.54％(0.04％-1.28％), and the average bias of the reference materials was 0.22％(-0.43％-0.68％). ForLC/MSmethod,the CV of instrument measurement was 0.55％(0％-1.68％),the total CV of samples measurement was 0.79％(0％-1.93％), and the average bias of the NIST reference materials was 0.09％(-0.73％-1.29％). No outlier was found from the scatter plots and the statistical analysis and the linear regression was fitted to analyze the results of the two methods. The linear regression parameters of two methods for 52 fresh frozen human sera were as follows:the slope was 0.9988,the standard error of slope was 0.0035, the intercept was 0.0037mmol/L, the standard error of intercept was 0.0030 mmol/L, the standard error of Y-estimate was 0.0236 mmol/L,and the correlation coefficient was 0.9997. Compared with the LC/MS method,the absolute deviation of fresh sera by HPLC method was-0.001 mmol/L (-0.070-0.056 mmol/L), with a relative deviation of 0.13％ (-2.01-2.83％). T-test showed no statistically significant difference between the two methods. The expected deviations at the triglycerides medicine decision level were within the 95％confidence range,and the expected deviations were far less than the allowable error. Conclusions The HPLC method of triglyceridesdetetion has good consistency and comparability with LC/MS method as one of the reference methods of CRMLN. Because of the advantages of HPLC method such as low cost, simplicity,less technical need,and better precision,HPLC method is expected to play an important role in the process of standardization and traceability of serum triglycerides.
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Objective To evaluate the commutability of 22 processed materials for serum alanine aminotransferase measurements which were performed in 11 routine assays without and 2 assays with pyridoxal-5′-phosphate.Methods 100 serum specimens were collected in Beijing Hospital,Zhao Yang Hospital and Tong Ren Hospital from May,2017 to August,2017.50 individual specimens together with fresh frozen human serum pools(HSPs), external quality assessment(EQA)materials, commercial calibrators and controls were measured by 11 routine assays without pyridoxal-5′-phosphate.Measurement results of the 50 individual samples were pairwise analyzed by Deming regression for slopes and intercepts, and 95%prediction interval(PI)were calculated to evaluate the commutability of processed materials.Another 50 individual specimens and 22 above-mentioned materials were analyzed by 2 assays with pyridoxal-5′-phosphate as the evaluated methods and internationally recognized reference method as the comparative method.The ordinary linear regression(OLR)and 95% PI were used to identify the commutability of 22 materials.Results The Deming slopes ranged from 0.879 to 1.064 and intercepts from -1.96 to 3.30;the OLR slopes were 0.905 and 0.955 while intercepts were -6.71 and 9.53.The HSPs were commutable for 51/57 and 56/57 assay pairs.The EQA materials, commercial calibrators and controls showed noncommutability from 8/57 to 47/57,38/57 and pairs after that, and from 13/57 to 43/57 assay pairs, respectively.Conclusion The lyophilized materials including EQA materials, commercial calibrators and controls demonstrated poor commutability in different degrees.
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Objective To establish a method for measuring blood phosphatidylethanol by liquid chromatography coupled with tandem mass spectrometry(LC-MS/MS), which can be applied for objective and quantitative of alcohol intake.Methods Whole blood samples were treated with isopropanol to precipitate protein,and phosphopropanol(16:0/16:0)was used as the standard.After centrifugation, the supernatants were transferred and evaporated under a stream of nitrogen until dryness.Then the residuals were analyzed by LC-MS/MS.Various methodological parameters, including linearity, limit of detection (LOD), limit of quantitation(LOQ), recovery, and precision, were investigated.Finally, blood samples from 40 Chinese individuals with more than one year of regular drinking habits were analyzed, and distributions of phosphatidylethanol were evaluated.Results The correlation coefficients were higher than 0.9992.The LOD and LOQ were lower than 0.74 and 2.48 ng/ml, respectively.The inter-and total assay coefficient of variations were 0.77%-3.18% and 2.30%-6.95%, respectively, with recoveries ranged from 96.88% to 102.99%.The relationship between phosphatidylethanol level and self-reported alcohol consumption was significantly and positively correlated(r =0.769, P <0.001).Furthermore, Kruskal-Wallis analysis showed a significant difference in total phosphatidylethanol levels among individuals with different levels of alcohol intake(χ2=18.850,P<0.001).Conclusions An LC-MS/MS method for whole blood phosphatidylethanol detection has been developed.This method is simple,sensitive and accurate and can effectively reflect light,moderate and heavy alcohol intake.The method will be applied to the assessment of alcohol consumption and its association with the risks of drinking related diseases.
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Objective Preparation of aqueous reference materials for cholesterol and glycerol.Methods Study on reference materials.The certified reference materials GBW09203b and GBW09149 were weighed accurately and dissolved into 20% of methyl cyclodextrin aqueous solution to prepare six kinds of candidate reference materials of cholesterol and glycerol according to the concentration.The materials were tested for homogeneity and stability using routine methods.The reference methods of isotope dilution liquid chromatography tandem mass spectrometry (ID-LC/MS/MS) were used to determine the concentration of cholesterol and glycerol to evaluate the accuracy of the certified values.Meanwhile, the blank verification test was carried out.The expanded uncertainty was the combination of standard uncertainty of measurement, unhomogeneity and instability.Results It showed that the six candidate reference materials were homogeneous and stable for at least 1 year at-70 ℃ and-20 ℃.The certified values (reference value ± expanded uncertainty,mmol/L) were as follows,for cholesterol:0.65±0.01,1.31 ±0.01,2.57±0.02,5.21±0.06,7.71±0.08,10.24±0.06;for glycerol:0.29±0.01,0.58±0.01,1.22±0.02,2.24±0.02,3.46±0.04,4.52 ±0.04.The results of reference methods were consistent with the certified values.Blank validation tests showed that the concentration of the analytes would not be affected by the reagent and the blank matrix.Conclusions Certified reference materials for cholesterol and glycerol in aqueous solution have been prepared successfully.These materials are homogeneous and stable, and the certified values are reliable.Therefore the materials have been approved to be the Certificate Reference Materials of GBW 09823, GBW 09824, GBW 09825, GBW09826, GBW09827 and GBW 09828.
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Objective Clinically, the anterior cruciate ligament ( ACL) can be reconstructed by either ligament advanced reinforcement system ( LARS) artificial ligament or hamstring tendon autograft ( HTAG) . This study aims to compare the early clinical outcomes of LARS versus HTAG in the treatment of ACL. Methods This study included 38 cases of ACL injury treated in our de-partment from March 2012 to August 2014, 18 by LARS artificial ligament and the other 20 by HTAG. Before and at 18 months after surgery, we evaluated the clinical outcomes of the tow strategies using the Lysholm knee scoring scale and International Knee Documen-tation Committee ( IKDC) scoring systems, and conducted statistical analysis on the follow-up findings. Results Statistically signifi-cant differences were not observed preoperatively between the LARS and HTAG groups either in the Lyshrolm scores (46.78±1.52 vs 46.80 ±1.89, P>0.05) or in the IKDC scores (42.83±1.47 vs 42.20±1.61, P>0.05), nor at 18 months postoperatively in the Lyshrolm scores (93.52±3.19 vs 94.10±1.37, P>0.05) or the IKDC scores (92.11± 1.45 vs 93.15±1.76, P>0.05). However, both the LARS and HTAG groups showed significant differences in the Lyshrolm and IKDC scores at the baseline as compared with those at 18 months after oper-ation ( P<0.05) . Conclusion Both LARS artificial ligament ham-string tendon autograft can achieve good early clinical outcomes in ACL reconstruction.
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The pediatric reference intervals in clinical laboratory play an important role in diagnosis of illness,therapeutic monitoring,prediction of prognosis and health evaluation.Compared with establishing reference interval for adults,there are more challenges to establish pediatric reference intervals.Therefore,the procedure and key technologies of direct method and indirect method are stated based on the characteristics of children population and pediatric,by which to define,transfer and validate pediatric reference intervals.This study will provide systematically methodological ideas for clinical laboratories to establish pediatric reference intervals.
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The incidence of thyroid dysfunction has increased year by year; the degree of public concern about thyroid disease also has been growing; the accuracy and comparability of results given by thyroid hormone assays from clinical laboratories face new challenges .This paper reviewed the clinical significance and measurements of thyroid hormones , also summarized the outcome of IFCC Working Group on Standardization of Thyroid Function Tests .It is expected to bring manufacturers′and clinical laboratories′attention to the importance of standardization/harmonization; and they could collaborate with each other .
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Objective To examine the stability of high-density lipoprotein cholesterol (HDL-C)during serum incubation at different temperature and time periods.Methods Ten healthy volunteers (4 males and 6 females,aged 24 to 59 years)from Beijing Hospital were recruited in May 2015.Fasting venous blood samples were collected and centrifuged to separate the sera.Serum samples were incubated at 4℃ for 24 h,25℃for 0,1,8 and 24 h (with or without an LCAT inhibitor).Serum to-tal cholesterol (TC),total free cholesterol (TFC)HDL-C and HDL-FC were measured by the HPLC Method.Results HDL-FC and HDL-C changed -6.91% and -2.17% during serum incubation at 4℃for 24h.TFC,HDL-FC and HDL-C changed significantly (averaged -13.70%,-25.88% and -1.53% respectively)during serum incubation at 25℃ for 24 h,in which the decrease of TFC and HDL-FC were inhibited by the addition of the LCAT inhibitor.The decrease of HDL-C was even higher in the presence of the LCAT inhibitor.Conclusion Serum TFC,HDL-C and HDL-FC levels changed during serum incubations,which were caused by the LCAT and CETP activities and the transfer of cholesterol among lipoproteins. For accurate measurement of serum HDL-C,prolonged serum storage should be avoided in clinical laboratories.
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The shoulder joint is the largest joint of range of motion in the human body,but the stability is relatively low.Ath-letes and soldiers who engage in the high strength training are prone to shoulder joint instability, while Bankart lesion is the common factor which leads to shoulder joint instability.With the invention of the new medical devices and updating therapeutic method, the treatment of Bankart lesions is improved continuously.In this paper, we will review the key points of diagnosis and therapeutic method.
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Quality indicator is defined as the measure used to access the degree of inherent characteristics meeting the requirements .It is a powerful tool to improve laboratory quality to monitor and evaluate performance throughout critical steps in the total testing process .Targeted quality improvement can be obtained by quantizing quality levels in each phase when the quality indicators applied .Establishing and monitoring the quality indicators enables laboratory to compare over time between providers , and evaluate the effectiveness of delivered services and improving patient safety .
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Objective To prepare the serum reference materials for total thyroxine .Methods Individual blood samples were collected from 13 healthy donors (7 males and 6 females) aged from 20 to 50 years old, and the sera were separated and mixed into 4 serum pools according to the concentration of thyroxine.The materials were tested for homogeneity and stability using routine methods .The method of isotope dilution liquid chromatography tandem mass spectrometry ( ID-LC/MS/MS) was used to determine the concentration of thyroxine .The candidate reference materials were also measured by four conventional methods to analyze the commutability of the materials .Results It showed that the four candidate reference materials were homogeneous and commutable in four conventional methods and they were tested to be stable for at least 1 year at -70 ℃using the isochronous stability study .The certified values ( reference value ± expanded uncertainty ,nmol/L) were:75.9 ±1.8,105.3 ±2.2,114.7 ±2.1 and 187.4 ±2.9.Conclusions Certified reference materials for serum thyroxine have been prepared .These materials have been approved to be the Certificate Reference Materials of GBW 09127,GBW 09128,GBW 09129 and GBW 09130.
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Objective To develop a solid phase extraction and Folin-Ciocalteu method for the measurement of total polyphenols in urine samples.Methods From a group of individuals attending an annual physical examination at Beijing hospital, 123 healthy volunteers (52 males and 71 females, ranging in age from 18 to 81 years ) were recruited during the period from December 2013 to April 2014.Urine samples were stored in 0.5%HCl at -80 ℃.For analysis, samples were applied to the Plexa PAX solid phase extraction cartridge, to purity the polyphenols through washing, evaporating and reconstituting.Total polyphenols were measured by Folin-Ciocalteu colorimetric assay, calculated by gallic acid standard curve, and corrected by urine creatinine concentrations.The relationship between total polyphenols and fruits and vegetable intake and cardiovascular disease risk factors were analyzed. Results Gallic acid standard solution and urine samples were stable in 0.5% HCl for 48 h at RT and 7days at 4 ℃, respectively.The PAX cartridge effectively eliminated the possible interfere materials in urine and had better recovery for most of the polyphenol types.The inter assay and total CVs for the measurement of total polyphenols were 2.7%-3.8% and 2.4%-4.6 %, respectively.Total polyphenol concentrations of 123 healthy subjects were 114.13(82.97-146.70) mg GAE/g Crea.Total polyphenol levels positively correlated with both HDL-C (r=0.194, P=0.032) and apoAI (r=0.312,P<0.001), and negatively correlated with serum uric acid levels(r=-0.220,P=0.014).Conclusions We established a measurement of total polyphenols in urine samples using solid phase extraction and Folin-Ciocalteu method.This simple, precise method reliable and may be use to assess dietary polyphenols intake.
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Isotope dilution mass spectrometry is a reliable principle for small molecule analyte measurements.It is a precise,accurate method with very high specificity,which is very suitable for lowconcentration steroid hormones tests.The published reference methods are all based on this principle so far.In this paper,the applications of isotope dilution mass spectrometry in the determination of steroid hormones were reviewed.
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Objective To evaluate the trueness of 13 routine measurements for serum uric acid and the role of reference method in improving harmonization and trueness among routine measurement systems. Methods The research is related to the reagent evaluation.Usingisotope dilution liquid chromatography tandem mass spectrometry ( ID-LC/MS/MS) method as the comparison method, Wako, Sekisui, DiaSys, Maker,Dirui,Leadman,BSBE,Biosina,Mindray,MedicalSystem,LongMarch,and Kehua 13 kinds of uric acid kits were chosen as the evaluation methods with Hitachi 7170A as the analyzer.serum uric acid in 40 fresh frozen serawere collected from clinical laboratory of Beijing hospital in 2014,coveringboth physiological and pathological status ( 80 -940 μmol/L ) .19 kinds of prepared materials and the 40 fronzen sera were measuredby comparison method and evaluation methods and linear regression analysis was made for the results.The performance of evaluation methods was revealed and recalibration was performed on every evaluation methodby the linear regression equation.The variation of percent bias(%) of the uric acid values in 19 preparation materials was compared.Results All test methods demonstrated good precision ( CV0.998, P<0.01) with the comparison method when measuring uric acid values in 40 fresh frozen sera The meanpercent bias was 0.17% ( -3.06% -7.31%).After recalibration, 4 of 19 samples with no matrix effect values percent bias reduced and met the demands of quality ( <4.8%) induced from biological variation.Conclusion All test methods demonstrated good trueness and their calibration traceability was verified.Recalibration using reference method or standard reference materials contributes to harmonization among methods.