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Objective:To develop a national secondary reference material of Urea and Creatinine in frozen human serum as a standard for metrological traceability.Methods:According to JJF1343-2012 "General and Statistical Principles for Characterization of Reference Materials" and JJF 1006-1994 " Technical Norm of Primary Reference Material ", the homogeneity, stability, and commutability were evaluated;Using the JCTLM recommended methods, the value of the reference materials was assigned through collaboration with 6 accredited reference laboratories from Guangdong Provincial Hospital of Chinese Medicine, Beijing Aerospace General Hospital, Shenzhen Mindray Bio-Medical Electronics, Maccura Biotechnology, Beijing Leadman Biochemistry, and Zhejiang MedicalSystem Biotechnology. Uncertainty components including inhomogeneity, stability and value assignment were evaluated.Results:The results of one-way analysis of variance of homogeneity for the reference materials showed P>0.05, and the stability evaluation was less than the critical value of the t-test. The measured values were in the 95% confidence interval in the four conventional detection systems for commutability, and the certified values and expanded uncertainties were urea:(14.7±0.3) mmol/L ( k=2),Cr:(313.9±14.5) μmol/L ( k=2). Conclusion:The prepared secondary reference materials of urea and creatinine had promising homogeneity, stability, and commutable, the values of urea and creatinine concentration in reference materials were accurate and reliable.
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Objective:To establish a candidate reference method for serum progesterone using isotope dilution liquid chromatography tandem mass spectrometry (ID-LC/MS/MS) in our laboratory, validate the analytic performance of five clinical routine detection systems to explore the comparability of serum progesterone detection by different detection systems.Methods:A candidate reference method for serum progesterone using ID-LC/MS/MS method was established. The sample was pretreated by liquid-liquid extraction method, and the reversed phase liquid phase separation in positive ion mass spectrometry mode was used to detect progesterone in human serum, and the detection time of a single sample was controlled within 5 minutes by gradient elution. In order to improve the accuracy of the method, the bracketing calibration method (BCM) was used to establish the standard curve. The sensitivity, accuracy, precision and specificity of BCM and classical calibration curve method were evaluated according to CLSI C62-A, EP15-A2, EP6-A2 and EP9-A3, and the analytical performance and comparability of five clinical routine progesterone detection systems were evaluated,compared with ID-LC/MS/MS method, the bias at medical decision level 2 and 25 ng/ml was evaluated to see if they were <1/2TEa (12.5%).Results:The limit of detection (LOD) of ID-LC/MS/MS was 0.005 ng/ml. The recoveries of BCM method and classical calibration curve method are 97.95%-101.58% and 96.88%-110.70%, respectively. The measurement results of BCM method for certified reference materials are within its declared uncertainty range. The intra-and inter-assay coefficient of variation ( CV) of BCM method was less than 3.0%, which was better than that of classical calibration curve method ( CV: 2.48%-9.33%). The precision and linear range of the five clinical routine detection systems can meet the detection requirements. The measurement bias of detection system 1, 3 and 5 at 25 ng/ml of medical decision level was less than 1/2TEa, and the measurement bias at 2 ng/ml of medical decision level was more than 1/2TEa. The measurement bias of detection system 2 and 4 at two medical decision levels was less than 1/2TEa. Conclusion:The candidate reference method for serum progesterone ID-LC/MS/MS established in our laboratory meets the requirements of the reference method. BCM has better detection performance than classical calibration curve method. The precision and linearity of the five progesterone clinical detection systems are satisfactory. The five clinical detection systems could meet the clinical requirements at the medical determination level of 25 ng/ml, however, only two of the five clinical detection systems meet the clinical requirements at the medical determination level of 2 ng/ml.
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Objective To express adenosine deaminase protein by molecular cloning technique.MethodsTotal RNA was extracted from human leukocytes and the cDNA was obtained by reverse transcription.Whereupon the cDNA was used as a template to amplify adenosine deaminase gene by polymerase chain reaction (PCR) and then integrated it into three prokaryotic plasmids pET-28 b, pET-32 a (+) and pHSIE.The plasmid with the correct sequencing was transformed into E.coli BL21 (DE3) by CaCl2 method for the protein expression.The expression activity of these fusion proteins were detected by Western-blot and SDS-PAGE, with the optimized expression conditions.Results Complete fusion of target gene and three prokaryotic plasmids was observed through sequencing.The expressed and accurate ADA protein was identified by Westernblot and SDS-PAGE.The optimal expression conditions were observed:the protein expression would be induced with 0.4 mmol/L IPTG and incubated at 16℃for 24 hours.Conclusion The prokaryotic vectors of adenosine deaminase (BL21+pET-28 b+ADA, BL21+pET-32 a+ADA, BL21+pHSIE+ADA) were successfully constructed and efficiently expressed.
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Objective To explore the feasibility of inter-laboratory comparison and trueness evaluation among clinical laboratories, and assess the quality of participants′measurement, by measuring the activity of alanine aminotransferase ( ALT ) in patient serum samples.Methods Method comparison study was used.Five patients serum samples, whose target values were assigned by two international candidate reference laboratory with reference method of ALT without pyridoxal phosphate, were measured by 23 routine laboratories.The bias between measurement result of each participant and the mean of reference laboratories was calculated, and then compared to allowable bias 6%.Calculate the mean value and the relative bias.Results Compared with the mean of reference laboratories, the maximum absolute value of bias among the 23 routine laboratories was 31.27%.The rate range which bias was less than the allowable bias was 26.09%-73.91 %.The bias acceptability of 8 participants were more than or equal to 80%;15 participants were less than or equal to 60%; and 3 participants were 0%.Conclusions Using patient serum samples and values assigned by reference method is an effective way to carry out inter-laboratory comparison and trueness evaluation.It can reflect the quality of measurement more truly.
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Warfarin is a well-accepted drug used for preventing thromboembolic diseases. It is important to monitor the dosage of warfarin. Prothrombin time is one of the screening tests of extrinsic coagulation path,which is the first choice to monitor the oral use of warfarin. Standardized prothrombin time, namely international normalized ratio ( INR ) is used to adjust warfarin dosage in clinical practice. Many herbal medicines and foods may enhance the effect of warfarin therapy,and some of them may weaken this effect,which can result in severe clinical complications.
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Objective To investigate the effects of interleukine-22 ( IL-22 ) on the expression of interleukin-6 (IL-6) by rheumatoid arthritis synovial fibroblasts (RASF), and to analyze their association with IL-17+CD4+T (Th17) cells differentiation.Methods RASF were isolated from six patients with rheu-matoid arthritis ( RA) and cultured in vitro.The expression of IL-6 at mRNA and protein levels by RASF were detected by qRT-PCR analysis and ELISA after treatment with different concentrations of IL -22 for dif-ferent periods of time.Anti-IL-22R1 blocking antibody and inhibitor assay were used to analyze the specific receptor and its downstream signaling pathways associated with IL-6 production.IL-22 pre-treated RASF and CD4+T cells were co-cultured for 3 days in the presence or absence of anti-IL-22R1 or anti-IL-6 to measure the percentage of Th 17 cells by flow cytometry .Results The expression of IL-6 by RASF was increased up-on IL-22 stimulation in a dose and time dependent manner (P<0.05), and that was closely related to IL-22R1 and its downstream signaling pathways of p38 and JAK2 (P<0.05).Co-culturing CD4+T cells with RASF and Transwell system indicated that the percentage of Th 17 cells was increased in IL-22 pre-treated group as compared with that in IL-22 untreated group , but it could be down-regulated by either blocking IL-22R1 or IL-6.Conclusion IL-22 promoted the expression of IL-6 by RASF and further enhanced Th 17 dif-ferentiation.Neutralizing IL-22 in synovium of patients with RA might be an effective therapeutic strategy for RA treatment.
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Objective To Evaluate the performance of serum adenosine deaminase assays of different manufacturers and explore the approach for harmonization of test results.Methods It was evaluated the indice including the limit of blank ,precision,linearity range and reference interval of 10 test systems.It was as the reference system by Mindray test system to evaluate the comparability and the difference of ADA results among 10 different systems.The evaluation was performed before and after calibration by a selected fresh serum assigned by the reference system.A commercial calibrator of the minimum matrix effect was selected from 8 different calibrators as the long-term calibrator to harmonize the ADA results of 10 systems.Results The results of LoB were 0.1-6.3 U/L,respectively.The within-run CVs and total CVs of 10 systems were all less than 5%and actual linearity ranges were conformed to claims of manufacturers.After calibration with fresh serum calibrator ,the averaged difference of 10 test systems was reduced from 14% to 3.0%, and the average difference was 1.8% after calibration with long-term calibrator.The common reference interval of all test systems was 5-24 U/L identically.Conclusions The comparability of ADA measurements can be improved by using a common human serum calibrator and the commutable commercial calibrator.And it is necessary and feasible to develop the standardzation of ADA.
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Objective To construct the recombinant plasmid pET32a-AKT1 and express human AKT1 protein using prokaryotic expression system .Methods Reverse transcriptase-polymerase chain reaction(RT-PCR) was employed to amplify the gene AKT1 in coding region and integrated it with pET 32a plasmid ,following by transforming it into Escherichia coli DH5α and prokaryotic strains BL21(DE3) .Isopropyl-beta-D-thiogalactopyranoside(IPTG) was adopted to induce its expression .Sodium dodecyl sulfate polyacrylamide gel electrophoresis(SDS-PAGE ) and Western-blot were used for protein identification .Results Complete fusion of target gene and plasmid was observed .The recombinant plasmid pET32a-AKT1 was successfully transferred into the strain DE3 . After IPTG induction ,protein with relative molecular mass 70 000 was expressed by DE3 .Conclusion The recombinant plasmid pET32a-AKT1 is constructed successfully and AKT 1 protein is completely and efficiently expressed by prokaryotic strain DE 3 .
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Objective To discuss the feasibility of enzymatic reference methods in Routine Chemistry external quality assessment (EQA)inlaboratorymedicine.Methods Samplesofthe1stEQAin2012byNationalCenterforClinicalLaboratories(NCCL)and patients′sera were measured by reference methods and 5 clinical analytic systems for the catalytic activity of CK ,LDH ,ALP ,ALT , AST ,GGT and AMY ,then the results of 5 clinical systems were compared with the reference methods′or target value of NCCL by calculating the bias ,and evaluated them according to the criteria of EQA by NCCL .Results The results of EQA samples measured by reference methods was within ± 10% compared with NCCL target value .Compared with the results of reference method ,the through put was 100 .0% for wet clinical chemistry systems measuring both EQA samples and patients′serum ,and the dry clinical chemistry systems was 77 .1 for EQA samples and 97 .1% for patients′serum according to the criterion of EQA ,and the through put was 72 .9% and 63 .6% of wet clinical chemistry systems according to the standard of enzymatic trueness of NCCL .Conclusion Reference method could be applied to EQA ,and will be a great help for the trueness of clinical testing .
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Objective To investigate the intralaboratury and interlabomtory variations of measurements for ALT and AST among four domestic reference laboratories. Methods The International Federation of Clinical Chemistry and Laboratory Medicine (IFCC) reference procedures and IFCC procedures without pyridoxal 5-phosphate (PLP) were performed in the reference laboratories. Intralaboratory and interlaboratory CVs were compared with those in 2006 and 2007 IFCC External Quality Assessment Scheme for Reference Laboratories (RELA). Meanwhile, deviations of results for ALT, AST and AST/ALT between two methods were calculated. Results Interlaboratory CVs were generally higher than intralaboratory CVs. Interlaboratory CVs among the 41 laboratories were lower than these in RELA. Results of ALT and AST using method with PLP were higher than those using method without PLP. Difference of AST/ALT ratio between the two methods was significant. Conclusions For reference measurement of the 2 enzymes, interlaboratory CVs of < 3.5 are achievable on frozen serum materials. Measurements on lyophilized materials may have higher CVs. Further studies are needed for the investigation of the differences between results obtained in the absence and presence of PLP.
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Objective To evaluate the measurement accuracy of serum gamma-glutamyltransferase (GGT) assays manufactured in China. Methods The International Federation of Clinical Chemistry and Laboratory Medicine (IFCC) reference method for GGT was set up and, after verification, was used to evaluate the performance of routine assay systems made in China. The evaluation was performed twice before and after a calibration by a common serum calibrator. Results For the reference measurement, the within run and total CVs were all less than 1%. The biases with the target values of IFCC External Quality Assessment Scheme for Reference Laboratories (RELA) were all within the limit of equivalence. Before a calibration with a common calibrator, the largest biases of results of GGT of the routine tasting systems compared with reference method at three medical decide levels were -47.53%, -34.11% and -30.07% respectively, and the averaged biases were 14.53% ,12.88% and 12.48%. After calibrating by fresh serum calibrator,the largest biases were reduced to - 17.63%, -5.88% and -4.08% ,the averaged biases were reduced to 7.50%, 2.70% and 1.87%. Conclusion The performance of GGT measurements can be effectively improved by using a common fresh serum calibrator that has a value assigned with the reference method.
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Objective To discuss the comparability of total bibe acidl(TBA) results among different detection systems.Methods 3 different kinds of coagulation detection systems were used to detect TBA concentration in 2 levels of Randox quality controls and 45 clinical sera according to EP9-A file.The collected data were dealt with statistical analysis.Results The analysis of variance showed TBA resulls from different control and patients sera had significant diffefence in different detection systems (P
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Objective To discuss the comparability of blood glucose(Glu)results with different detection systems.Methods Six different kinds of biochemistry detection systems were used to detect plasma Glu concentrations at 2 levels of Randox quality controls and 48 clinical plasma according to EP9-A file.The collected data were treated with statistical analysis.Results Analysis of variance showed Glu results from different control and patients plasma had significant difference between various detection systems (P
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AIM: To study the serum level of interferon ( IFN)-?, IFN-?, nitric oxide (NO) and nitric oxied synthase (iNOS) in severe ac ute respiratory syndrome (SARS) patients and to expl ore its significance. METHODS: IFN-?, IFN-?, NO and iNOS were determined in SARS patients during the early, recovery and follow-up stage, the health doctors and nurses and health people, respectively. RESULTS : The serum level of IFN-? during the early stage was higher than that of other groups (P