Participation In External Quality Assessment Schemes Research Articles

Experience of external quality assessment scheme in hematology at Shantabaa Medical College, Amreli: An observational 5-year study

Background: The complete blood count is one of the most frequently requested tests in laboratory medicine. External quality assessment programs are intended to allow medical laboratories to compare the closeness of their output (test results) to their peers through statistical evaluation against a target value. External quality assessment schemes (EQAS) are accepted around the world as an invaluable tool by laboratories to assess the performance of their testing systems. Results are objectively compared to other laboratories, using the same methodologies for every parameter. Aims and Objectives: To review EQAS results from time to time in an effort to improve the performance of the laboratory. Materials and Methods: An observational study is done for hematology EQAS test results at the hematology laboratory, Shantabaa Medical College and General Hospital, Amreli, from June 2017 to August 2021 (5 years). One ethylenediaminetetraacetic acid whole blood sample for blood cell counts and two slides for peripheral smear examination and reticulocyte count are received quarterly in a year from all India Institute of Medical Science, New Delhi. The test results of all Indices of blood samples and peripheral smears for cell morphology and reticulocyte count were analyzed and documented. Results: Satisfactory results were obtained in all the cycles except once. The discrepancy was observed in RBC, MCH, and reticulocyte count. Root cause analysis was performed and necessary action was taken. Conclusion: This participation in EQAS over the past 5 years has helped us significantly to improve our laboratory services in terms of performance evaluation, patient care, and overall quality of laboratory practices.

Precision and accuracy of commercial assays for vancomycin therapeutic drug monitoring: evaluation based on external quality assessment scheme.

Vancomycin remains a mainstay of the treatment of Gram-positive bacterial infections. It is crucial to accurately determine vancomycin serum concentration for adequate dose adjustment. To evaluate the precision and accuracy of commercial assay techniques for vancomycin concentration and to assess the comparability of vancomycin detection methods in Chinese laboratories. Human serum samples spiked with known concentrations of vancomycin were provided to laboratories participating in the external quality assessment scheme (EQAS). Assay methods included chemiluminescence, enzyme immunoassay (EIA) and so on. The dispersion of the measurements was analysed and the robust coefficient of variation (rCV), relative percentage difference (RPD) and satisfactory rate for method groups were calculated. Moreover, performance of the Chinese laboratories was assessed. A total of 657 results from 75 laboratories were collected, including 84 samples from 10 Chinese laboratories. The median rCV, median RPD and satisfactory rates classified by methods ranged from 1.85% to 15.87%, -14.75% to 13.34% and 94.59% to 100.00%, respectively. Significant differences were seen in precision, between kinetic interaction of microparticles in solution (KIMS) and other methods, and in accuracy, between enzyme-multiplied immunoassay technique (EMIT), fluorescence polarization immunoassay (FPIA) and other techniques. Vancomycin detection in China mainly depended on the chemiluminescence and EMIT methods, which tended to result in lower measurements. Although almost all assays in this study achieved an acceptable performance for vancomycin serum concentration monitoring, obvious inconsistencies between methods were still observed. Chinese laboratories were more likely to underestimate vancomycin concentrations. Thus, recognizing inconsistencies between methods and regular participation in vancomycin EQAS are essential.

External quality assessment (EQA) and alternative assessment procedures (AAPs) in molecular diagnostics: findings of an international survey.

Quality management for clinical laboratories requires the establishment of internal procedures including standard operating procedures (SOPs), internal quality control (QC), validation of test results and quality assessment. External quality assessment (EQA) and alternativeassessment procedures (AAPs) are part of the quality hierarchy required for diagnostic testing. The International Organization for Standardization (ISO) document with requirements for conformance ISO 15189 and the Clinical and Laboratory Standards Institute document (CLSI) QMS24 require participation in EQA schemes and AAPs where applicable. The purpose of this study was to perform a global survey of EQA and AAPs for key procedures in molecular diagnostic laboratories. The Committee for Molecular Diagnostics of the International Federation of Clinical Chemistry and Laboratory Medicine (IFCC C-MD) conducted a survey of international molecular laboratories that covered specific topics of molecular diagnostic services as well as methods for EQA and AAPs. The survey addressed the following aspects: (1) usage of laboratory-developed test (LDT), (2) participation in EQA schemes and (3) performance of AAPs. A total of 93 responses from laboratories located in Asia, Europe, the Middle East, North America and South America were received. The majority of the participating laboratories (65.9%) use LDTs and 81.3% stated that it is mandatory for them to participate in EQA programs, while 22% of the laboratories reported not performing AAPs. Thirty-one percent of the laboratories use EQAs for fewer than 50.0% of their reported parameters/analytes. While the majority of laboratories perform EQA and AAPs to improve their quality in molecular diagnostics, the amount of AAPs as quality procedures differs within the laboratories. Further surveys are necessary to clarify the existing needs in additional EQAs and standardized AAPs. The survey will also guide future efforts of the IFCC C-MD for identifying quality practices in need to improve harmonization and standardization within molecular diagnostics.

External quality assessment for molecular diagnostic laboratories in Belgium: Can we improve it?

External quality assessment (EQA) is an essential part of performance monitoring for molecular laboratories. At the moment, a national law regulates participation in EQA schemes for clinical biology and pathology in Belgium. This study aimed (1) to get insights on how laboratories organize their EQA participation, (2) to poll satisfaction with the current situation (selection of EQA programs in advance by a governmental body), (3) to provide guidance for choosing the most relevant EQA provider and (4) to propose a new model for national performance monitoring. A survey was sent to Belgian laboratories performing molecular tests in the field of microbiology, hematology and pathology with (1) general questions on how they select an EQA provider and (2) their satisfaction of each provider. In total, 25 molecular laboratories [microbiology (N = 13), hematology (N = 8) and pathology (N = 4)] from 14 different hospitals completed the survey regarding their EQA organization. All three laboratory groups indicated to prefer EQA schemes using real patient materials as well as those with varying targets and concentrations. For molecular microbiology and hematology, schemes with a syndromic approach are sought. Since annual participation in EQA becomes burdensome in most laboratories, this paper also offers a risk-based strategy for determining the participation frequency. Based on the needs of Belgian laboratories, three proposals were made: (1) for the proper selection of an EQA scheme, (2) for determining the minimal participation frequency and (3) for the national organization of EQA schemes.

Clinical interpretation of prostate-specific antigen values: Type of applied cut-off value exceeds methods bias as the major source of variation.

Prostate-specific antigen is the biochemical gold standard for the (early) detection and monitoring of prostate cancer. Interpretation of prostate-specific antigen is both dependent on the method and cut-off. The aim of this study was to examine the effect of method-specific differences and cut-off values in a national external quality assessment scheme (EQAS). The Dutch EQAS for prostate-specific antigen comprised an annual distribution of 12 control materials. The results of two distributions were combined with the corresponding cut-off value. Differences between methods were quantified by simple linear regression based on the all laboratory trimmed mean. To assess the clinical consequence of method-specific differences and cut-off values, a clinical data-set of 1040 patients with an initial prostate-specific antigen measurement and concomitant conclusive prostate biopsy was retrospectively collected. Sensitivity and specificity for prostate cancer were calculated for all EQAS participants individually. In the Netherlands, seven different prostate-specific antigen methods are used. Interestingly, 67% of these laboratories apply age-specific cut-off values. Methods showed a maximal relative difference of 26%, which were not reflected in the cut-off values. The largest differences were caused by the type of cut-off, for example in the Roche group the cut-off value differed maximal 217%. Clinically, a fixed prostate-specific antigen cut-off has a higher sensitivity than an age-specific cut-off (mean 89% range 86-93% versus 79% range 63-95%, respectively). This study shows that the differences in cut-off values exceed the method-specific differences. These results emphasize the need for (inter)national harmonization/standardization programmes including cut-off values to allow for laboratory-independent clinical decision-making.

The external quality assessment scheme in Haematology: Ten years experience as a participating laboratory

Background: The attainment of quality services in a laboratory requires a comprehensive Quality Assurance Programme which includes both Internal and External quality control material. External Quality Assessment Scheme (EQAS) programmes are accepted around the world as invaluable tools by laboratories to assess the performance of their testing systems. Results are objectively compared to other laboratories, using the same methodologies for every parameter. Aim: The goal of this study was to review EQAS results from time to time in an effort to improve the performance of the laboratory. Settings and Design: Observational study done at Pramukhswami Medical College, Shree Krishna Hospital, Karamsad from January 2003 to December 2013. Material and Methods: In the current study we have evaluated our EQAS test result of the past ten years, from 2003 to 2013. We receive one EDTA whole blood sample for blood cell counts and 2 slides for peripheral smear examination and reticulocyte count respectively. It is received quaterly in a year. The test results of all blood samples and peripheral smears for cell morphology and reticulocyte count were analyzed and documented. Results: Satisfactory results were obtained in all the cycles except two times. Discrepancy was observed in white blood cell (WBC) counts. Root cause analysis was performed and necessary action taken. Conclusions: This participation in EQAS over the last ten years has helped us significantly to improve our laboratory services in terms of performance evaluation, patient care and overall quality of laboratory practices.

External quality assessment of HbA1c and its effect on comparison between Swedish pediatric diabetes clinics. Experiences from the Swedish pediatric diabetes quality register (Swediabkids) and Equalis

To explore to what extent measurement error can explain the variation of mean patient HbA(1c) between clinics. For each year 2005-2010 data from 5380-6985 children, age <18 years, in 35-43 Swedish pediatric clinics was analyzed. Each year 13,000-19,000 HbA(1c) analyses were evaluated. Year mean HbA(1c) for each patient was calculated for HbA(1c) values when insulin dose was ≥0.5 U/kg. In Sweden HbA(1c) values were during the study period standardized to the Mono S level, HbA(1c)(Mono S)%, but are given also in the international unit HbA(1c)(IFCC), mmol/mol. Performance of locally measured HbA(1c) is monitored by Equalis through monthly external quality assessment (EQA) schemes. The yearly mean bias term for each clinic varied from -0.54 to 0.41 HbA(1c)(Mono S)%. The bias between clinic HbA(1c) and target value improved during the 6 years and the mean bias was for 79%-88% of clinics within the recommended level ±0.14 HbA(1c)% the last 2 years. Inter-clinic mean HbA(1c) had a wide interquartile range, 0.30-0.43 HbA(1c)(Mono S)% [3.2-4.5 HbA(1c)(IFCC)mmol/mol]. Regular participation in EQA schemes is necessary when comparing HbA(1c) values. The measurement error decreased during the 6-year period and explained from 28% to <10% of the inter-clinic variation in year mean clinic HbA(1c).

Instability of mercury in specimens of human urine for external quality assessment

An under-recovery of inorganic mercury added to urine and a wide range of results is observed in quality assessment schemes (EQAS) for trace elements. Further- more, the under-recoveries are inconsistent suggesting features associated with the urine matrix may make the mercury unavailable for measurement. To investigate the instability of mercury in urine the following experiments were set up: (1) a sample of Hg 2? in water with various 'stabilizers' added was sent to UK external quality assessment scheme participants. (2) Urine was collected from volunteers who also completed a 3-day food diary. Hg, Ca, Mg, Se, uric acid, phosphate, creatinine, reducing substances and protein were measured. Inorganic mercury was spiked into the urine, stabilizers were added and the mercury determined following storage. The results con- firmed under-recovery of mercury in association with the urine matrix. Further investigations of how urinary com- ponents affect the measurement of mercury are necessary.

Variability in the use of CE-marked assays for in vitro diagnostics of CFTR gene mutations in European genetic testing laboratories

DNA diagnostics of genetic diseases increasingly shifts towards utilization of commercial assays. Cystic fibrosis (CF)-related DNA diagnostics were used as a model for a pilot survey of the variability in the utilization of qualitative CE-marked in vitro diagnostic (IVD) assays and the scale of their modification by end users. A structured questionnaire, developed in the context of the EuroGentest project, was distributed within the frame of the 2005 annual CF external quality assessment (EQA) scheme. Its aim was to evaluate the variability in the use of different CE-marked IVD assays in routine CF DNA diagnostics. Survey results were analysed and sequentially discussed with respective users and/or manufacturers. In total, 125 responses from EQA scheme participants were received. Almost half of the respondents modified manufacturer-recommended protocols. They also reported sporadic and/or recurrent problems with assay performance and genotyping of particular alleles. Nonetheless, only half of the respondents performed in-house verification before the implementation of the assay in clinical diagnostics and/or after modification of the recommended protocol. Results of this survey substantiate the importance of guidelines for proper verification of CE-marked IVD assays in DNA diagnostics, using CF as a model.

EQAS for peripheral blood morphology in Spain: a 6‐year experience

The Spanish haematology external quality assessment scheme (EQAS), established in 1984, is run by the Spanish Haematology and Haemotherapy Association (AEHH) [Quality Assurance in Health Care 3 (1991) 75] and functions to evaluate the quality and reproducibility of the assessment of diagnostic samples by clinical laboratories. The Hospital Clinic of the University of Barcelona (HCB) serves as the EQAS Coordination Centre and follows the guidelines established by the International Committee for Standardization in Haematology [Annali dell'Istituto superiore di Sanità 31 (1995) 95; International Journal of Hematology 68 (1998) 45]. During the period 2001-2006, replicates of 25 different blood films were sent to 604 EQAS participants for cell morphology evaluation. Some patient details corresponding to the samples were disclosed, such us age, sex, haemoglobin value and white blood cell count. The participants were asked to select up to four significant morphology features using a coding list, provided by the Coordination Centre, which included significant morphological alterations that appear in haematopoietic cells. For each survey, individual results were assessed against the morphological reference results (MRR) established by the Cytology Group of the AEHH ('true' answers). This paper describes the organization of the 6-year-long study and the evaluation of laboratory performance for blood smear interpretation by the Spanish haematology EQAS. Different performance levels were detected relative to the laboratory category. Laboratories providing services to hospitalized patients showed higher performances compared with laboratories providing services to nonhospitalized patients. Pathological lymphoid cells were the most difficult to identify by the participants. To improve the results in EQAS peripheral blood morphology, the development of specific cytology educational trainings is discussed.

Point of care testing by health care professionals: current practice amongst the UK National External Quality Assessment Scheme Participants

Point of care testing by health care professionals: current practice amongst the UK National External Quality Assessment Scheme Participants

A survey of workload, facilities and awareness of uncertainty of measurement among Italian laboratories performing analyses in occupational and environmental medicine

Biological monitoring is essential for risk assessment in the presence of exposure of workers or the general population to harmful chemical agents. Besides the choice of analytical methods which are fit for purpose and the skills of the analysts, the performance of laboratories, including those working in the field of environmental and occupational medicine, also depends on other technical factors such as frequency of testing, the use of well maintained and properly functioning equipment and the implementation of quality control procedures including the participation in External Quality Assessment Schemes (EQAS). Surveys of laboratory workload have been organized periodically since 1997 within the MeTos Project, an Italian national EQAS for biomarkers of environmental and occupational exposure to chemical agents. In 2001, a more extensive survey, including specific technical issues, was organized as part of the activities of the Thematic Network of European Organizers of External Quality Assessment/Proficiency Testing Schemes Related to Occupational and Environmental Medicine (Network survey). In addition, information on the awareness and implementation of the new requirement for laboratories to estimate the uncertainty of their measurements was collected since 2000. The results of these surveys are reported and compared here. In all surveys, Pb in blood was the biomarker most frequently determined. As for biomarkers of exposure to organic compounds, the data collected in the Network survey indicate that methylhippuric acid, hippuric acid and mandelic acid in urine were the assays most commonly performed. About a third of the participants stated that they estimate the uncertainty of at least some of their measurements. Preliminary analysis of data, limited to Pb in blood, showed that analytical performance improved with continuous participation in EQAS and was positively influenced by a high workload.

Twenty years of the Me.Tos. Project: an Italian national external quality assessment scheme for trace elements in biological fluids

The Me.Tos. Project, started in 1983 and still running, is an external quality assessment (EQA) scheme for laboratories performing specialized analyses in occupational and environmental laboratory medicine. Besides the organization of EQA exercises, initiatives for further education of the participants and the harmonization of EQA procedures at a European level are carried out. Participation in EQA schemes allows laboratories to comply with the international standards for the quality and competence of testing and clinical laboratories. The organization of the scheme includes the preparation of control materials, their distribution to the participants, according to strategies aimed to avoid identification of the samples, the statistical analysis of the results and the evaluation of laboratories' performance according to international guidelines and criteria set by the organizers. An overview of the scheme operation and the current performances of participants will be given.

Quality assurance in biological monitoring of environmental exposure to pollutants: from reference materials to external quality assessment schemes

The presence of chemicals in the environment is a matter of concern in that it poses potential health risks. At present, exposure to toxic chemicals and their biological and biochemical effects can be better estimated by biological monitoring, through the systematic collection of specimens from potentially exposed humans. Biological monitoring of human exposure to environmental pollutants is hampered by the difficulty to assess data reliability. As a consequence, the validity of biological monitoring should depend on the strict implementation of a quality assurance (QA) program, which includes a series of procedures aiming to ensure that laboratory results meet defined standards of quality and are reliable. For the validation and monitoring of methods’ performance, to ensure the trueness of measurements and to warrant the traceability to international standards, reference materials (RMs) and certified reference materials should be used. Internal quality control and external quality assessment (EQA) are part of overall QA and are carried out to verify that analytical errors are compatible with the specific requirements or needs of the user. In particular EQA schemes (EQAS) allow to test independently the analytical performance of participating laboratories. In the last decades, increasing concern has been raised by urban air pollution; lead and benzene, two gasoline components released by motor vehicle exhausts, are known to be toxic to humans. For biological monitoring of lead exposure of the general population, screening campaigns, utilizing lead in blood as a biomarker, have been carried out since the 1970s. Strict strategies were adopted to ensure data comparability, including the preparation of RMs, the organization of EQAS and the cross-exchange and analysis of blood samples between laboratories. Biological monitoring of benzene exposure could be carried out by means of various biomarkers such as benzene in blood and benzene, trans,trans-muconic acid (t,t-MA) and S-phenylmercapturic acid (S-PMA) in urine. At present, few RMs and EQAS are available for these biomarkers. A pilot EQAS for t,t-MA in urine, adopted to assess the reliability of data regarding benzene exposure, has been organized and carried out between 1996 and 1997 in Italy. From the accrued experience, it clearly emerges the importance of strategies designed to guarantee the quality of biological monitoring data. The use of RMs and the participation in EQAS are highly recommended in order to improve the global performance of methods and laboratories involved in biological monitoring.

External Quality Assessment of Microbial Counts from Water: To Score or Not to Score for Proficiency

Scoring schemes were first introduced in water-chemistry inter-laboratory proficiency tests. Such scoring does not behave in a comparable manner when applied to microbiology external quality assessment. Conventional scores can become a lottery. This poses a challenge to (a) find helpful statistical methods which will look beyond this natural variation and (b) attempt to identify any poor performance by the participants. The aim is to provide useful management tools. In the Public Health Laboratory Service, water external quality assessment scheme participants have detected methodology problems. Formal analyses are carried out on cumulated results in two stages, first demonstrating whether there is any systematic difference between laboratories of microbiological as well as statistical significance and only then allocating participants to categories of acceptable, or poor, performance. The scheme has been operating for several years and performance improvements are evident.