ABSTRACT
Objective To analyze the reference intervals of serum total bilirubin (TBIL) and serum direct bilirubin (DBIL) by all Chinese clinical laboratories and make a comparison with the upcoming part 4 of Industry Standard WS/T 404.Methods Relevant information about reference intervals of all clinical laboratories participating in TBIL and DBIL testing items of 2014 national external quality assessment scheme of clinical routine chemistry was collected by a web-based external quality assessment software,including source,grouping,verification,upper and lower limits of reference intervals and instruments,reagents,methods and calibrators used.Microsoft Excel 2010 and SPSS 19.0 were applied to statistical analysis.The comparison between reference intervals used and the upcoming Industry Standard was conducted by the simple mean t test.Laboratories derived from the highest percentage of source distribution whose reagent and instrument were matching with each other were grouped according to the test systems used and the differences of reference intervals between three mainly used test systems and the upcoming Industry Standard were also compared with the single sample mean t test.Results The number of laboratories participated in the investigation about source distribution of reference intervals for TBIL and DBIL was 749 and 709 respectively.For these two items,the highest sources were both instructions of reagent(TBIL 58.08％,DBIL 58.67 ％),next were both National Clinical Laboratory Operation Rules (3rd Edition) (TBIL 29.64 ％,DBIL 28.91 ％),the percentages of other sources were all less than 10％.Besides,there were respectively 379 (50.60％) and 354 (49.93％) laboratories verifying their reference intervals for TBIL and DBIL.The difference of the comparison between reference intervals used and the upcoming Industry Standard had statistical significance (P＜0.05).The using reference intervals were narrower than the upcoming Industry Standard for both items.In all laboratories with reference intervals from instructions of reagent,themating laboratories respectively accounted for 41.88％ and 41.48％％ for item TBIL and DBIL.As the single sample mean t test showed,the comparison of the reference intervals between three mainly used test systems in these mating laboratories and the upcoming Industry Standard had statistical significance (P＜0.05),except for the lower limit of DBIL with Beckman test system (P value was 0.068) and the upper limit of DBIL with HITACHI test system (P value was 0.087).Conclusion Currently,the using situation of reference intervals about TBIL and DBIL by all Chinese laboratories was not scientific and rational enough and has significant difference with the upcoming Industry Standard.Should publish the part 4 of Industry Standard WS/T 404 as soon as possible,which would help clinical laboratories establishing suitable reference intervals and promote the standardization of its usage.
ABSTRACT
In clinical laboratory medicine,measurement uncertainty (MU) is a fixed property of testing results in the measuring system.As an important part of ISO 15189,it is necessary for clinical laboratories to determine MU during the period of validation and verification for each measurement procedure and to review MU over time.Now,testing reports provided by clinical laboratories usually do not offer MU,but some clinical laboratories have already estimated MU in their routine work.Estimation andmonitoring of MU can help clinical laboratories offering more accurate results and provide objective tools for clinicians used in result intcrpretatinn.Generally,result interpretation can be achieved by the result comparison with three main comparators,including a previous result from the same patient,a population reference interval and a clinical decision point.The means of true value and the components contributing to the estimation of MU are both different when the com parison is conducted between testing results and different comparators,so the optimum estimation method of MU is accordingly different,which will subsequently affect the MU value and the determination of clinical decisions.Obviously,depending on the actual clinical uses,laboratories can choose appropriate comparators to the result interpretation and the determination of optimum estimation method of MU.For different clinical uses (diagnosis or monitoring) of the same mearurands,the adoption of different estimation methods should be used to acq uire reasonable MU.By interpreting the concept,characteristics,estimation,and uses of MU,as well as explaining how three main comparison methods of results exploit their own traceable chain to get MU,this paper intends to help clinical laboratories get further understanding of the importancc of MU and provide guidance for the MU estimation in routine work.
ABSTRACT
In the clinical laboratory medicine,the measurement uncertainty (MU)is a relatively new concept.Over the years, experts of clinical laboratory medicine from all over the world made a great number of further researches and promote the development of MU,which led clinical laboratories to pay more and more attention to the meanings and functions of MU at the same time.However,because of the habitual using of the total error (TE)in clinical laboratories and similarities between concepts of MU and TE which easily resulted in confusion,a lot of laboratories still cannot completely accept MU.By explai-ning concepts of TE and MU and analyzing the pros and cons of models of TE and MU as well as their functions,the obj ec-tive of this paper is to help clinical laboratories make further comprehensions of TE and MU and understand how to properly use them in practice.
ABSTRACT
Objective Discussthe reference intervals and their sources of lymphocyte subsets by flow cytometry tests by all Chinese clinical laboratories at 2014 with a comparison of difference between different test systems.Methods Questionnaires about reference intervals were distributed to 212 clinical laboratories participating in October 2014 national external quality assessment scheme of lymphocyte subsets by flow cytometry tests of National Center for Clinical Laboratory.Relevant information about reference intervals of 5 relative counting items CD3 + (％),CD3 + CD4 + (％),CD3 + CD8 + (％),CD3-CD16 + CD56 + (％) and CD3-CD19 + (％) was collected by a internet-based external quality assessment software systems.Microsoft Excel 2010 and SPSS 19.0 were used to sort out raw data,eliminate unreasonable or incorrect data,and only analyze source distribution,arithmetic average,median,minimum value,maximum value and percentiles (P2.5 and P97.5) of upper and lower limits about healthy adults' reference intervals.Laboratories derived from the highest percentage of source distribution whose reagent and instrument were matching with each other were grouped according to the test systems used and the differences of reference intervals between different systems were compared with Mann-Whitney test.Results For five items collected,in the clinical laboratories who accepted statistical analysis,respectively 39.32％ (81/ 206),37.44％ (79/211),37.68％ (78/207),37.11％ (72/194),36.98％ (71/192) of them had verified the reference intervals they used.The top three sources of reference intervals were instructions of reagent and instrument manufactures (49.70％-52.54％),calculations by laboratories themselves (18.64％-20.00％),and calculations by other laboratories (14.12％-15.43％).The arithmetic averages and medians of upper and lower limits about every item were relatively close.But the minimum and maximum values of upper and lower limits of certain items had moderate differences.As Mann-Whitney test later showed,all items with the P values of upper and lower limits between different test systems,except for the lower limit of CD3 + CD4 + (％) (P value is 0.052) and the upper limit of CD3-CD19 + (％) (P value is 0.117),were lower than 0.05 which meant an existing statistical difference.Conclusions The sources of lymphocyte subsets by flow cytometry tests in all Chinese clinical laboratories were different and the instructions of reagent and instrument had the highest percentage,but the reference intervals among differenttest systems had statistically significance.