Milan – The new hierarchy: Update from the EFLM strategic conference on defining analytical performance goals. Quality specifications for QC and QAP

Pathology ◽  
2016 ◽  
Vol 48 ◽  
pp. S16
Author(s):  
Graham Jones
Author(s):  
Callum G. Fraser

AbstractThe setting of analytical quality specifications in laboratory medicine has been a topic of discussion and debate for over 50 years: 15 years ago, as the subject matured and a profusion of recommendations appeared, many of them from expert groups, it was realised by a number of leading professionals that there was a need for a global consensus on the setting of such specifications. The Stockholm Conference held in 1999 on “Strategies to set global analytical quality specifications in laboratory medicine” achieved this and advocated the ubiquitous application of a hierarchical structure of approaches. The hierarchy has five levels, namely: 1) evaluation of the effect of analytical performance on clinical outcomes in specific clinical settings; 2) evaluation of the effect of analytical performance on clinical decisions in general using a) data based on components of biological variation, or b) analysis of clinicians’ opinions; 3) published professional recommendations from a) national and international expert bodies, or b) expert local groups or individuals; 4) performance goals set by a) regulatory bodies, or b) organisers of external quality assessment (EQA) schemes; and 5) goals based on the current state of the art as a) demonstrated by data from EQA or proficiency testing scheme, or b) found in current publications on methodology. This approach has been much used since its wide promulgation, but there have been ongoing criticisms and new developments. The time seems right for an objective reappraisal of recommended strategies to set analytical performance goals.


Author(s):  
Carmen Perich ◽  
Carmen Ricós ◽  
Fernando Marqués ◽  
Joana Minchinela ◽  
Angel Salas ◽  
...  

AbstractThe purpose of this study is to understand the evolution of the analytical performance of the laboratories participating in the Spanish society of laboratory medicine (SEQCML) external quality assurance (EQA) programmes during its 30 years of operation and to compare it with the performance of other EQA programmes to establish whether the results are similar. The results obtained during this period are evaluated by applying the biological variability (BV) and state of the art-derived quality specifications. In addition, the results are compared with those obtained by other EQA programme organisations. It is noted that the laboratories participating in the EQA–SEQCML programmes have improved their performance over 30 years of experience and that the specifications derived from biological variation are achievable. It is difficult to compare EQA programmes, due to lack of accessibility and the differences in the design of these programmes (control materials, calculations used and analytical specifications established). The data from this study show that for some biological magnitudes the results obtained by the programmes are not yet harmonised, although efforts are being made to achieve this. Organisers of EQA programmes should also join the harmonisation effort by providing information on their results to enable comparison.


2012 ◽  
Vol 58 (12) ◽  
pp. 1703-1710 ◽  
Author(s):  
Yeo-Min Yun ◽  
Julianne Cook Botelho ◽  
Donald W Chandler ◽  
Alex Katayev ◽  
William L Roberts ◽  
...  

BACKGROUND Testosterone measurements that are accurate, reliable, and comparable across methodologies are crucial to improving public health. Current US Food and Drug Administration–cleared testosterone assays have important limitations. We sought to develop assay performance requirements on the basis of biological variation that allow physiologic changes to be distinguished from assay analytical errors. METHODS From literature review, the technical advisory subcommittee of the Partnership for the Accurate Testing of Hormones compiled a database of articles regarding analytical and biological variability of testosterone. These data, mostly from direct immunoassay-based methodologies, were used to specify analytical performance goals derived from within- and between-person variability of testosterone. RESULTS The allowable limits of desirable imprecision and bias on the basis of currently available biological variation data were 5.3% and 6.4%, respectively. The total error goal was 16.7%. From recent College of American Pathologists proficiency survey data, most currently available testosterone assays missed these analytical performance goals by wide margins. Data from the recently established CDC Hormone Standardization program showed that although the overall mean bias of selected certified assays was within 6.4%, individual sample measurements could show large variability in terms of precision, bias, and total error. CONCLUSIONS Because accurate measurement of testosterone across a wide range of concentrations [approximately 2–2000 ng/dL (0.069–69.4 nmol/L)] is important, we recommend using available data on biological variation to calculate performance criteria across the full range of expected values. Additional studies should be conducted to obtain biological variation data on testosterone from women and children, and revisions should be made to the analytical goals for these patient populations.


1993 ◽  
Vol 39 (7) ◽  
pp. 1525-1529 ◽  
Author(s):  
H A Fritsche ◽  
R J Babaian

Abstract We have assessed the feasibility of using fixed-limit criteria based on medical relevance and biological variation for evaluating the analytical performance of the prostate-specific antigen (PSA) test. The estimated within-subject variation of serum PSA is on the order of 10-20% at clinical decision points. The calculated performance goals of 5-10% CV are attainable with current immunoassay technology and agree with precision goals based on clinical experience and the current clinical use of the test. However, new clinical applications of PSA may require a degree of analytical performance that current methods may not be able to provide. The PSA model demonstrates the need for biologically based fixed-limit criteria for all tumor-marker tests.


Author(s):  
Per Hyltoft Petersen ◽  
Esther A. Jensen ◽  
Ivan Brandslund

AbstractWith the increasing use of decision limits (action limits, cut-off points) specified for a number of analytical components in diagnosis and for action in critical situations, formulated in national or international recommendations, the traditional interpretation of reference intervals has been uncertain, and sometimes the two concepts are being mixed up by incorporating risk calculations in the reference intervals. There is, therefore, a need to clarify the two concepts and to keep them definitely separated. Reference intervals are the 95% limits for the descriptions of the distributions of the values of analytical components measured on reference samples from reference individuals. Decision limits are based on guidelines from national and international expert groups defining specific concentrations of certain components as limits for decision about diagnosis or well-defined specific actions. Analytical quality specifications for reference intervals have been defined for bias since the 1990s, but in the recommendations specified in the clinical guidelines analytical quality specifications are only scarcely defined. The demands for negligible biases are, however, even more essential for decision limits, as the choice is no longer left to the clinician, but emerge directly from the concentration. Even a small bias will change the number of diseased individuals, so the demands for negligible biases are obvious. A view over the analytical quality as published gives a variable picture of bias for many components, but with many examples of considerable bias which must be critical – yet no specifications have been stipulated until now.


2017 ◽  
Vol 4 ◽  
pp. 205435811769335 ◽  
Author(s):  
Elizabeth Sunmin Lee ◽  
Christine P. Collier ◽  
Christine A. White

Author(s):  
Rainer Haeckel ◽  
Werner Wosniok ◽  
Thomas Streichert

AbstractThe organizers of the first EFLM Strategic Conference “Defining analytical performance goals” identified three models for defining analytical performance goals in laboratory medicine. Whereas the highest level of model 1 (outcome studies) is difficult to implement, the other levels are more or less based on subjective opinions of experts, with models 2 (based on biological variation) and 3 (defined by the state-of-the-art) being more objective. A working group of the German Society of Clinical Chemistry and Laboratory Medicine (DGKL) proposes a combination of models 2 and 3 to overcome some disadvantages inherent to both models. In the new model, the permissible imprecision is not defined as a constant proportion of biological variation but by a non-linear relationship between permissible analytical and biological variation. Furthermore, the permissible imprecision is referred to the target quantity value. The biological variation is derived from the reference interval, if appropriate, after logarithmic transformation of the reference limits.


2006 ◽  
Vol 96 (11) ◽  
pp. 584-589 ◽  
Author(s):  
Frits Haverkate ◽  
Cornelis Kluft ◽  
Piet Meijer

SummaryTo achieve a reliable analytical quality for both monitoring and diagnostic testing, laboratories need to fulfil the widely accepted analytical performance goals based on the biological variation of the analytes of testing. Not only is the short-term analytical performance, which regularly is assessed by internal quality control procedures, of importance, but also the long-term analytical performance. To assess the long-term analytical performance, data obtained from an external quality assessment programme can be used. In this study we have used the evaluation model designed by the ECAT Foundation for the assessment of the longterm analytical performance, including imprecision, bias and total analytical error. The model was applied to the data from 136 different laboratories for the assay of antithrombin (activity), protein C (activity and antigen) and protein S (activity, total and free antigen). The imprecision (median; range), reflected by the long-term analytical coefficient of variation (LCVA), was the lowest for antithrombin (7.6%; 2.6 – 43.8%) and the highest for protein S activity (17.2%; 4.3 – 88.6%). For bias and total error the same pattern was observed (antithrombin: 3.8%; 0.3 – 17.1% and 9.1%; 3.4 – 34.3%, respectively; protein S activity: 12.8%; 3.1 – 34.8% and 24.5%; 9.9 – 87.0%, respectively). For the majority of the laboratories (70 – 85%) the imprecision contributes considerably more to the total error than the bias. However the effect of the bias on the analytical quality is not negligible. Assays for antithrombin, protein C and protein S are mainly used for diagnostic testing. About 70 – 100% of the laboratories can fulfil the desirable performance goal for imprecision. The desirable performance goal for bias was reached by 50 – 95% of the laboratories. In all cases the highest numbers of laboratories fulfilling performance goals was obtained for the protein C variables. To improve the analytical quality in assays of antithrombin, protein C and protein S it is highly recommended that primarily imprecision (non-systematic failures) be suppressed. However the effect of the bias (systematic failures) on the analytical quality should not be neglected. A useful tool for determining the imprecision (LCVA) and bias is the long-term analytical performance evaluation model as used by the ECAT Foundation.


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