Analytical performance specifications for external quality assessment – definitions and descriptions

Author(s):  
Graham R.D. Jones ◽  
Stephanie Albarede ◽  
Dagmar Kesseler ◽  
Finlay MacKenzie ◽  
Joy Mammen ◽  
...  

AbstractExternal Quality Assurance (EQA) is vital to ensure acceptable analytical quality in medical laboratories. A key component of an EQA scheme is an analytical performance specification (APS) for each measurand that a laboratory can use to assess the extent of deviation of the obtained results from the target value. A consensus conference held in Milan in 2014 has proposed three models to set APS and these can be applied to setting APS for EQA. A goal arising from this conference is the harmonisation of EQA APS between different schemes to deliver consistent quality messages to laboratories irrespective of location and the choice of EQA provider. At this time there are wide differences in the APS used in different EQA schemes for the same measurands. Contributing factors to this variation are that the APS in different schemes are established using different criteria, applied to different types of data (e.g. single data points, multiple data points), used for different goals (e.g. improvement of analytical quality; licensing), and with the aim of eliciting different responses from participants. This paper provides recommendations from the European Federation of Laboratory Medicine (EFLM) Task and Finish Group on Performance Specifications for External Quality Assurance Schemes (TFG-APSEQA) and on clear terminology for EQA APS. The recommended terminology covers six elements required to understand APS: 1) a statement on the EQA material matrix and its commutability; 2) the method used to assign the target value; 3) the data set to which APS are applied; 4) the applicable analytical property being assessed (i.e. total error, bias, imprecision, uncertainty); 5) the rationale for the selection of the APS; and 6) the type of the Milan model(s) used to set the APS. The terminology is required for EQA participants and other interested parties to understand the meaning of meeting or not meeting APS.

2020 ◽  
Vol 58 (4) ◽  
pp. 588-596
Author(s):  
Anne Stavelin ◽  
Kristine Flesche ◽  
Mette Tollaanes ◽  
Nina Gade Christensen ◽  
Sverre Sandberg

AbstractBackgroundIt has been debated whether point-of care (POC) glycated hemoglobin (HbA1c) measurements methods can be used for diagnosing persons with diabetes mellitus. The aim of this study was to evaluate the analytical performance of the POC Afinion HbA1c system in the hands of the users, and to investigate which predictors that were associated with good participant performance.MethodsExternal quality assurance (EQA) data from seven surveys in 2017–2018 with a total of 5809 Afinion participants from a POC total quality system in Norway were included in this study (response rate 90%). The control materials were freshly drawn pooled EDTA whole blood. Each participant was evaluated against the analytical performance specification of ±6% from the target value, while the Afinion system was evaluated against the pooled within-laboratory CV <2%, the between-laboratory CV <3.5%, and bias <0.3%HbA1c. Logistic regression analyses were used to investigate which factors were associated with good participant performance.ResultsThe participant pass rates for each survey varied from 98.2% to 99.7%. The pooled within-laboratory CV varied from 1.3% to 1.5%, the between-laboratory CV varied from 1.5% to 2.1%, and bias varied between −0.17 and −0.01 %HbA1c in all surveys. Reagent lot was the only independent factor to predict good participant performance.ConclusionsAfinion HbA1c fulfilled the analytical performance specifications and is robust in the hands of the users. It can therefore be used both in diagnosing and monitoring persons with diabetes mellitus, given that the instrument is monitored by an EQA system.


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.


1996 ◽  
Vol 42 (9) ◽  
pp. 1478-1482 ◽  
Author(s):  
D Chesher ◽  
L Burnett

Abstract We have investigated the application of Shewhart's p control charts in our external quality-assurance program to monitor the long-term performance of our laboratory's analytical quality. The p control charts have been able to detect long-term changes in our laboratory's analytical performance that would have been difficult to detect by more-conventional techniques. We have explored methods for interpreting these charts as well as some of their limitations, which include minimum subgroup size and dependence on constant specification limits. These charts may be not only a simple method for the long-term monitoring of analytical performance of a laboratory, but also of use to the organizers of external quality-assurance programs.


Author(s):  
Tone Bukve ◽  
Thomas Røraas ◽  
Berit Oddny Riksheim ◽  
Nina Gade Christensen ◽  
Sverre Sandberg

AbstractThe Norwegian Quality Improvement of Primary Care Laboratories (Noklus) offers external quality assurance (EQA) schemes (EQASs) for urine albumin (UA) annually. This study analyzed the EQA results to determine how the analytical quality of UA analysis in general practice (GP) offices developed between 1998 (n=473) and 2012 (n=1160).Two EQA urine samples were distributed yearly to the participants by mail. The participants measured the UA of each sample and returned the results together with information about their instrument, the profession and number of employees at the office, frequency of internal quality control (IQC), and number of analyses per month. In the feedback report, they received an assessment of their analytical performance.The number of years that the GP office had participated in Noklus was inversely related to the percentage of “poor” results for quantitative but not semiquantitative instruments. The analytical quality improved for participants using quantitative instruments who received an initial assessment of “poor” and who subsequently changed their instrument. Participants using reagents that had expired or were within 3 months of the expiration date performed worse than those using reagents that were expiring in more than 3 months.Continuous participation in the Noklus program improved the performance of quantitative UA analyses at GP offices. This is probably in part attributable to the complete Noklus quality system, whereby in addition to participating in EQAS, participants are visited by laboratory consultants who examine their procedures and provide practical advice and education regarding the use of different instruments.


Author(s):  
Graham Ross Dallas Jones

AbstractExternal Quality Assurance (EQA) is a vital tool in laboratory medicine to assess individual laboratory analytical performance and also the differences between the results from different laboratories. This information is also useful for professional bodies and manufacturers as part of post-market surveillance. The process involves the measurement of one or more samples by many laboratories and then assessment of the results. Individual results are generally assessed by how far they lie from a target, which may be established using reference methods or a median of some or all of the submitted results. The distance of a result from the target is compared with analytical performance specifications in order to assess the analytical quality. One of the uses of the Stockholm hierarchy of performance goals is to set the performance specifications for analysis of EQA results. Fifteen years after the Stockholm consensus meeting, EQA analytical performance specifications appear to still vary widely between EQA providers. This can be due to a range of factors, including the rationale for setting the criteria, the expected response to a failure to meet the specified performance, the clinical meaning behind meeting the specifications, and the possible need for further analytical improvements. There are also differences in the models chosen to set the criteria, usually either state of the art or biological variation, and then differences in how these are applied. While harmonisation of EQA performance specifications may be some time off, all EQA providers should define the nature of their specifications and the basis for their selection and make this information available to customers.


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