| Objectives:At present,the accuracy and comparability of antithrombin,protein C,protein S activity testing,vWF activity and antigen testing is not so good in partial domestic clinical laboratories.It is imperative to prepare reference materials to help carry out quality improvement.The comparability among different systems was studied and the commutability of the candidate reference materials for AT,PC,PS activity testing,vWF activity and antigen testing prepared by NCCL were evaluated.The calibrating results of different calibrator were discussed in order to provide evidence for harmonization and quality improvement.Methods:1.The national investigation of the current status:The information of AT,PC and PS testing in domestic clinical laboratories were collected and analyzed by questionnaire survey and quality control material testing survey,including the methods of testing and the number of specimens,instruments and reagents,performance verification and calibration,reference intervals setting,figuring out present situation and problems existed.2.Issues related with harmonization of antithrombin testing result ?Performance verification of testing systems:according to foreign literatures and guidelines,as well as the manufacturers,the performance verification of AT,PC and PS activity testing of Sysmex CS-5100 coagulation instruments were conducted,including witin-run precision,between-run precision,calibration,accuracy and linear range verification.? The comparability of results among mainstream manufactures:The results of AT,PC and PS activity testing were verificated respectively in Sysmex,Stago and IL according to EP9-A3.?The preparation and evaluation of reference materials:3 lots of reference materials were prepared.According to ISO Guide35,CNAS-GL03,CLSI EP30-A,the homogeneity,stability and commutability of the reference materials were evaluated.According to ISO Guide 35,several laboratories with 3 kinds of detection systems(Sysmex,Stago and IL)were selected in target value study using NIB SC coagulation standard material as a standard for traceability.?The evaluation of calibrating results of different calibrator:The detection systems were calibrated respectively with manufacture matching calibrators,LOT4 and homemade high concentration reference materials,the changes of comparability of testing results between systems in different calibrating conditions were evaluated.?Applying reference materials in IQC:The reference materials were applied in internal quality control.The accumulated CV were calculated and compared with that of the manufacture matching quality control materials3.Issues related with harmonization of vWF testing results:?Evaluation of the stability of reference materials:The stability of the candidate reference materials for vWF activity and antigen testing prepared by NCCL were evaluated.? Issues related with harmonization of testing results:The comparability of vWF antigen testing result between Stago and IL was analyzed and the homogeneity of reference materials were evaluated.Laboratories were selected in target value determination study with Stago and IL detection systems using NIBSC coagulation standard material LOT4 as traceable standard.Results:1.Investigation of questionnaire and quality control materials testing:Two hundred and thirty-five questionnaires were collected.The number of laboratories testing antithrombin(AT),protein C(PC)and protein S(PS)activity were 194,63 and 50 respectively.The instruments and reagents were mainly from abroad(more than 96%),the matching rate of which were above 94%.For AT,PC and PS activity testing,there were 30.4%,33.3%,34.0%of laboratories did not perform verification assays respectively,and 8.8%,7.9%,14.0%of laboratories did not renew calibration curve when the reagent lots were changed.11.3%,17.5%,16.0%of laboratories didn't run internal quality control,and 34.9%,26.9%,21.4%of laboratories only performed a single level of quality control.4.1%of laboratories set the reference intervals of AT activity according to different age groups,and the percentage of that of PC and PS activity were 1.6%and 2.0%.16.0%of laboratories set the reference interval of PS activity by sex.For normal control materials,the CV of AT,PC and PS activity results were 5.7%-12.9%,4.2%-7.7%and 18.4%-33.1%while the CV for abnormal level were 13.3%-38.3%,6.1%-14.4%and 31.5%-34.5%respectively.The pass rate was different when it was judged by different criteria.A suitable criterion for each item should be selected according to the concentration level of quality control materials.2.Issues related with harmonization of antithrombin testing results:?The performance verification method and index of AT,PC,PS activity testing of Sysmex CS-5100 coagulation instrument was definited and the within-run precision,between-run precision,calibration,linear range and trueness verification can meet the requirements.?For AT and PC activity testing results,correlation among Sysmex,Stago and IL detection systems were good(r2>0.95).For PS activity testing results,the correlation coefficient between IL and Stago was greater than 0.90,which was acceptable,so as the result between IL and Sysmex,however,the results between Stago and Sysmex was not so good,r2<0.90.The comparability of PC activity testing can meet the BV-TEaoptimal level among Sysmex,Stago and IL.For AT and PC activity testing results,the comparability can meet the BV-TEamnmum.level.?3 lots reference materials had good homogeneity,the single factor ANOVA evaluation results showed that there were no statistically significant differences,P>0.05.The uncertainty of between-bottle homogeneity(ubb)of AT,PC and PS were 0.71%-1.27%.0.83%-1.20%and 0.91%-3.74%respectively.Reference materials were stored at-80?.AT,PC and PS activity testing results showed no trendency change during the observation period of 8 weeks,which implied the stabilities were great.The uncertainty of long-term stability(ults)were 1.06%-1.78%,1.57-2.97%and 1.45%-7.32%,respctively.All Reference materials were commutable for the three measurement systems.The average of the testing results by 5 laboratories were considered as the target value and the uncertainty of the procedure of the characterization study(uchar)were 1.89%-2.38%,1.96%-3.13%and 1.88%-7.57%.The values of AT201701 to AT201703 reference materials were(92.514.8)%9(78.9±3.8)%and(33.4±5.1)%,respectively.The values of PC201701 to AT201703 reference materials were(111.4±6.3)%,(85.3±6.4)%and(41.713.9)%,respectively.The values of PS201701 to AT201703 reference materials were(98.9115.1)%,(65.719.0)%and(31.2±3.8)%respectively·? The comparability of the results of AT activity testing between Stago and Sysmex can meet the BV-TEaminimum,the BV-TEadesirable and the BV-TEadesirable level after calibrating with manufacture matching calibrator,LOT4 and homemade reference materials respectively.The comparability of all the results of PC activity testing can meet the BV-TEaminimum level.The comparability of the results of PS activity testing can meet BV-TEadesirable,BV-TEadesirabie and the standard of RCPA.?The application of internal quality control showed that the CV of AT,PC,PS activity testing between reference materials and relevant concentration commodity quality control materials were 2.5-7.6%and 3.0-8.3%,2.3-2.6%and 2.0-4.0%,5.8-7.1%and 5.9-9.6%respectively,which were all less than the between-run imprecision of manufacture.3.Issues related with vWF testing result harmonization:?The vWF:Ag testing results showed no tendency change in 26 months,while The vWF:A testing results showed no tendency change in 11 months.Uncertainty of long-term stability(ults)of each lot were 0.70%-1.78%and 2.16%-4.56%respectively.?The comparability between IL and Stago can meet the BV-TEadesirable level.Lot4 and reference materials were commutable between the two detection systems.The values of vWF:Ag 201501-201505 reference materials were(138± 11)%,(89914)%,(544±3)%,(21 ±2)%and(1212)%.Conclusions:1.The survey results showed that the performance verification and quality control for anticoagulant proteins testing were lack of standardization in partial laboratories and the comparability of testing results were not satisfactory in different laboratories.In order to promote quality improvement,it is necessary to develop guidelines,organize trainings and establish a national EQA scheme.2.?The performance verification of the testing in our laboratory was validated,which fit the requirements of manufacture and relevant guidelines.The schemes for performance validation can be used as a reference in other laboratories.? The correlation of AT activity testing results was good among Sysmex,Stago and IL systems,so as PC.The comparability of PS activity was acceptable though the correlation of PS activity testing results was not good.?AT,PC and PS reference materials showed good homogeneity,stability and commutability among the 3 mainstream testing systems.Reference materials was characterized by 5 laboratories using 3 kinds of main detection systems.?Lot4 and homemade reference materials can be used as calibrator,which would not lower the comparability among detection systems apparently.?The CV accumulated of the reference materials are comparable with the commodity quality control materials,which can be applied to daily internal quality control.3.The stability of vWF reference materials(Antigen and activity)were good with commutability among the 2 mainstream testing systems.Reference materials was characterized by 8 laboratories.The comparability between IL and Stago can meet the requirement of BV-TEaaesirable level. |
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