Laboratory Proficiency Testing Research Articles

Evaluation of the targeted uncertainty in routine coagulation assay using EQA data

Objective To establish the target measurement uncertainty(MU) of the routine coagulation assay according to the External Quality Assessment data (EQA) of routine coagulation assay. Methods Beijing Center for Clinical Laboratory (BCCL) established the target measurementuncertainty for routine coagulation assayswith theup-downmethodon the basis of 93 clinical laboratoriesEQA datain BeijingThese assays includedActivated partial thromboplastine time(APTT), Fibrinogen(FBG), International Normalized Ratio(INR), Prothrombin time(PT), Thrombin time(TT) and D-dimer, Compared with CLIA′88, the proficiency of current coagulation assayswas observed. Results The MU of six routine coagulation assayscompared with CLIA ′88 showed that: The 90th percentile MU met the creteriain APTTof group B, FBG of group A&B&C, INR of group B and D-dimer of group B. The 75th percentile MU met the creteriainINR of group A&C, PT of group C. The medium met the creteriainAPTT of group A&C, PT of group A and INR of group D. Conclusions Target Measurement Uncertainty was establishedin routine coagulation assay by using EQA data only, whichcan simplify the procedure of determining MU and continuously update MU according to the frequency of EQA. It has good clinical practical value. However, the applicability of this method should also be considered.(Chin J Lab Med, 2017, 40: 942-946) Key words: Diagnostic tests, routine; Blood coagulation tests; Reference values; Uncertainty; Laboratories, hospital; Laboratory proficiency testing

Proficiency Testing of Clinical Laboratories for Bacteriology in the Philippines, 2009–2015

Introduction. SThe National External Quality Assessment Scheme (NEQAS) has been established by the Department of Health–Philippines (DOH) to provide DOH-approved external quality assessment programs, including the Proficiency Test (PT) for Bacteriology to clinical laboratories. The PT for Bacteriology aims to monitor and evaluate laboratory capabilities in the identification of clinically important pathogens through proficiency testing. Since then, participation in the NEQAS has been a requirement for clinical laboratories to obtain a license to operate from the DOH–Health Facilities and Services Regulatory Bureau (HFSRB). Objective. The objective of this report is to summarize and examine the results of the PT for Bacteriology from 2009 to 2015 and the performances of participating clinical laboratories throughout the Philippines. Methodology. The Research Institute for Tropical Medicine National Reference Laboratory (RITM-NRL) conducted orientation seminars between 2008 and 2009 to introduce clinical laboratories to the NEQAS. Laboratories submitted their accomplished enrolment forms to RITM–NRL and paid the fees to enroll in the PT. Participating laboratories were required to identify three analytes and perform antimicrobial susceptibility test (AST) on one assigned analyte. Results. A total of 468 laboratories participated over the seven-year period. The number of participating laboratories obtaining a passing score of 80% and above had significantly increased from 2009 to 2015. Out of the 144 laboratories consistently enrolled over the seven-year period, the proportion of participants with scores of 80% and above had increased. Of the 468 participating laboratories throughout 2009 to 2015, 33.3% were good performers; 6.6% were fair performers; and 60.0% were poor performers. Conclusion. The increasing number of participating laboratories obtaining passing scores over the years suggests overall improvement of the performance of clinical laboratories in bacteriology. Corrective actions are still needed to address the situation regarding the poor performing laboratories. The assessments done in 2008 and 2013 found that poorly performing laboratories lack trained personnel, resources, and implementation of quality assurance procedures for bacteriological testing.

Production and characterization of a traceable NORM material and its use in proficiency testing of gamma-ray spectrometry laboratories

This paper outlines the process of characterizing a new NORM material for proficiency testing made of quartz sand with significantly elevated levels of 226Ra obtained from the backflush of a drinking water treatment facility. Samples of the fully characterized NORM material were sent to European laboratories concerned with radioactivity measurements and environmental monitoring by gamma-ray spectrometry for proficiency testing. The paper discusses the results, specific requirements, problems and solutions that were found during the characterization process and the proficiency test.

An inter- laboratory proficiency testing exercise for rabies diagnosis in Latin America and the Caribbean.

The direct fluorescent antibody test (DFA), is performed in all rabies reference laboratories across Latin America and the Caribbean (LAC). Despite DFA being a critical capacity in the control of rabies, there is not a standardized protocol in the region. We describe the results of the first inter-laboratory proficiency exercise of national rabies laboratories in LAC countries as part of the regional efforts towards dog-maintained rabies elimination in the American region. Twenty three laboratories affiliated to the Ministries of Health and Ministries of Agriculture participated in this exercise. In addition, the laboratories completed an online questionnaire to assess laboratory practices. Answers to the online questionnaire indicated large variability in the laboratories throughput, equipment used, protocols availability, quality control standards and biosafety requirements. Our results will inform actions to improve and harmonize laboratory rabies capacities across LAC in support for the regional efforts towards elimination of dog-maintained rabies.

Robust Statistics Analysis and Difference Significance Test of the Test Data of Laboratory Proficiency Testing

Statistical analysis of the results in laboratory proficiency testing occupies an important position in the verification activities, this article reviewed the most widely used method in laboratory proficiency testing called robust statistical Z-Score, and a statistical analysis of the results was done with the application of SPSS software, F test was applied to the results which were divided into different groups according to the different test methods each laboratory used. It is helpful to determine whether each test method has significant effects on the results of laboratory testing and a further analysis.

Multiresidue method for the determination of pesticides in Oolong tea using QuEChERS by gas chromatography-triple quadrupole tandem mass spectrometry.

We propose a simple, rapid analytical method for determination of 89 pesticides in Oolong tea by GC/MS/MS. Samples were extracted via QuEChERS. The limits of detection and quantification range of the 89 pesticides were 1-25μgL-1 and 10-50μgL-1, respectively. Good separation was attained in less than 36min. A wide linear range of 1-250μgL-1 was observed with r2 values from 0.9955 to 0.9998. Pesticide-free tea powder spiked at 50 and 100μgL-1. Recovery ranges of the 86 (50μgL-1) and 83 (100μgL-1) pesticides were from 60% to 120%. Relative standard deviations were less than 20%. The laboratory proficiency test (FAPAS, 2014) shows satisfactory (|z|<2) z-score values. The proposed monitoring technique rapidly and efficiently screens, multiple pesticides in Oolong tea.

Proficiency testing of sampling.

Proficiency testing of analytical laboratories is now ubiquitous-laboratories need to participate regularly to receive accreditation. The outcome helps participants to detect unexpected sources of uncertainty. But sampling, as well as analysis per se, introduces its own uncertainty in most types of analysis. Sampling uncertainty arises partly from heterogeneity in the 'target' (the particular mass of material for which the sample is a surrogate), but also from variation in the manner in which the sample is extracted. Different samplers will do the job somewhat differently, even when following a single protocol. The potential value of proficiency tests for sampling is therefore obvious. And in recent years, feasibility studies and schemes have appeared in several application sectors. Different sectors have very different constraints on how sampling and proficiency testing can be carried out. Nevertheless, the need for general guidelines is obvious.

Development of certified reference material of mineral composition of natural water designed to control of turbidity measurement accuracy

Introduction. The results of development of a certified reference material (CRM) of mineral composition of natural water are presented. A solution prepared from the material of the CRM specimen imitates mineral composition of natural surface water. The certified values are mass fractions of nitrate ions, chloride ions, fluoride ions, and total iron and turbidity according to formazine scale. Materials and methods. The certified values of mass concentrations of the components were determined using calculated experimental evaluation procedure;the certified turbidity value was determinedusing the certified turbidimetric method. Results. The relative expanded uncertainty (k = 2) of the certified turbidity values does not exceed 5 %, the same value for mass concentrationsis not more than 3.5 %. Relative standard uncertainty from heterogeneity does not exceed 1.0 %. The shelf life of the developed CRM is set to 3 years. Discussion and conclusion. Developed CRM was registered in the State Register of CRM's as GSO 10815-2016. The CRM is designed to control the accuracy of results of the certified characteristics measurements, including proficiency testing of laboratories using interlaboratory comparative tests. The CRM can be used for validation of measurement procedures.

Implementing a regional integrated laboratory proficiency testing scheme for peripheral health facilities in East Africa.

IntroductionRegular participation in external quality assessment (EQA) is critical for maintaining laboratory performance and is required for laboratory accreditation. Proficiency testing (PT) is effective for providing EQA, but available schemes rarely address the range of tests performed by peripheral laboratories in resource-limited settings. The East African Regional External Quality Assessment Scheme (EA-REQAS) was established in 2004 to address this need.Materials and methodsSurveys were distributed biannually comprising seven different panel materials and questions addressing laboratory, clinical and public health topics. Preserved materials were prepared using standard procedures and validated by accredited laboratories to establish target values. Survey materials were shipped by courier and results returned by paper copy, email or online. Immediate feedback reports included advice for addressing errors. Composite reports addressing participants’ performance were provided to national quality assurance offices.ResultsSixteen surveys were distributed between 2008 and 2015; enrolment increased from 195 to 560 facilities. Mean response rate remained static (56-59%), but overall number of participating facilities increased. Mean performance scores increased from 51% to 68% but remained below the accepted score of 80%; individual facilities achieving 80% or more increased from 0 to 25%. Facilities participating in 10 or more surveys performed better than facilities participating in 5 or less surveys.ConclusionPT can be applied at peripheral level in resource-limited settings and identifies poorly performing areas. PT can also be used to assess performance of equipment and test kits as part of post-market surveillance. Smaller health facilities require additional support to address deficiencies.

The clinical application and common questions regarding IQCP

Individualized Quality Control Plan (IQCP) is a method of quality control for total testing process. In January 2016, the United States formally adopted the IQCP instead of the original equivalent quality control. This article will introduce how to establish and implement IQCP in the laboratory, and discuss the common problems in the process of its application.(Chin J Lab Med, 2016, 39: 876-878) Key words: Quality control; Laboratory proficiency testing; Risk assessment

Cell and Tissue Display: An Alternative Multipurpose Tool for Microscopy.

We developed a method, termed Cell and Tissue Display (CTD), for embedding 16 or more different tissue samples in multi-compartment agarose blocks. The CTD-generated blocks allow uniform multiplexing of cell lines and small tissue fragments within a single histologic block. The distribution of individual cells within the CTD blocks is improved, likely because the individual agarose compartments are small and uniform. The composition of each CTD block can be customized based on intended use. Some potential uses of CTD histologic blocks include improved sectioning of small tissue fragments, such as needle biopsy specimens or punch biopsies; multiplexing of tissue fragments within a single block; and the generation of control slides for laboratory proficiency testing. .

Highly accurate molecular genetic testing for HFE hereditary hemochromatosis: results from 10 years of blinded proficiency surveys by the College of American Pathologists.

The College of American Pathologists offers blinded proficiency testing (PT) for laboratories performing HFE genetic tests for hereditary hemochromatosis (common C282Y and H63D variants). This study used 10 years of PT data to determine laboratory performance for HFE analytical genotyping and clinical interpretation. Laboratories were graded for accuracy of genotype determination (six possible C282Y/H63D genotypes) and clinical interpretation regarding whether the genotype was likely to have contributed to iron overload in a hypothetical patient. The analytical genotyping error rate was low (0.73%) in 7,663 results (from 257 unique laboratories). Genotyping errors were significantly higher in C282Y heterozygous, H63D homozygous, and C282Y homozygous samples, in non-American laboratories, and in laboratories with lower testing volume. Analytical sensitivity and specificity were >98.5 and >99.5%. The interpretive error rate (4.3%) was higher than the genotyping error rate, with two problematic genotypes (C282Y heterozygous and H63D homozygous) accounting for 77% of total interpretive errors. There was a time-dependent improvement in the interpretation of the clinical significance of HFE genotypes. HFE molecular genetic testing, performed by non-US Food and Drug Administration-approved laboratory-developed tests, demonstrated excellent accuracy, sensitivity, and specificity. Clinical interpretations were more heterogeneous, probably owing to the low clinical penetrance of some common HFE genotypes.Genet Med 18 12, 1206-1213.

Proficiency testing: binary data analysis

A method for evaluating qualitative proficiency testing (PT) of laboratories conducting binary tests is proposed. The method is based on the scale-invariant item response model proposed by the authors in earlier publications. We consider the case where the laboratories under the PT conduct test consisting of a set of test items/species presenting different, but unknown beforehand levels of difficulty when trying to detect a particular property of theirs, and we need to evaluate/compare both the intrinsic abilities of the participating laboratories and the level of difficulty of the test items. We assume that the responses to different test items do not affect one another and discuss how to get and interpret the most likely estimates/scores. The method is illustrated by the example presented in a recent publication by our colleagues from QuoData GmbH and can be considered as an alternative to that proposed in their publication method of scoring.

Present status and future prospect of accreditation of proficiency testing provider in the area of laboratory medicine in China

The accreditation of Proficiency Testing Provider(PTP)has gone through more than a decade in China. Over the past ten years, from nonexistence to existence, the domestic PTPs in the area of laboratory medicine have gradually standardized and developed. By reviewing the international and domestic practice, this paper gives an outline of the present status of the accreditation of PTP in the area of laboratory medicine, explores the difference with other countries, the main problems and some suggestions for improvement, and makes a prospect of the development of the accreditation of PTP in the area of laboratory medicine in China.(Chin J Lab Med, 2016, 39: 326-328) Key words: Laboratory proficiency testing; Health personnel; Accreditation; Clinical trial

HPLC를 이용한 아족시스트로빈과 이미다클로프리드, 메타벤즈티아주론의 토양 잔류분석 숙련도시험

Abstract The proficiency testing for the residue laboratories of pesticide registration was conducted inorder to improve the reliability and the ability for pesticide residue analysis. On November 2012 the testingwas carried out using the soil collected and kept as the moistened state for five years, which was expected tovery low residue levels of pesticides. The soil was fortified with azoxystrobin, imidacloprid and methabenz-thiazuron in a manner similar to prepare soil samples for indoor soil degradation test, and then sub-sampleswere prepared for the distribution to participants. Some of them were randomly selected for confirm ofhomogeneity and to ensure the stability of samples at room temperature. Samples were consisted of two soilstreated as different levels, one of which was used to the assessment and another used to confirm. In addition,provided three standard solutions, respectively concentration of 10 mg/L, and untreated soil. Forty eightinstitutions submitted results. The medians of results were used as the assigned values for pesticide residues.Fitness for purpose standard deviation of proficiency test was calculated by applying 20% RSD as thecoefficient of variation allowed in the soil residue test. Z-score was applied for evaluation of individualpesticides, and the average of the absolute value of the Z-score for the overall assessment of pesticides.Laboratories evaluated the absolute value of the Z-score less than 2 to fit the case of azoxystrobin were 48,imidacloprid and methabenzthiazuron 46.Key words pesticide, residue analysis, quality assurance, proficiency test

Study of appropriateness of laboratory reports for clinical hematology in China

Objective To investigate the status of report appropriateness in Clinical Hematology and to identify its potential influence factors to improve the quality of laboratory reports. Methods 1 120 National External Quality Assessment(EQA) participants laboratories were enrolled in this study. The questionnaires were assigned to all the participants in both electronic and printed form. The participants were asked to retrospectively count the total reports and the affected reports while the following quality indicators occurred in 2012: report delay, inconformity of data between instrument and LIS as well as between report and request erroneous report transportation, report recall, and report modification. All quality indicators were evaluated in two ways: percentage and sigma (σ) scale. Mann-Whitney Test and Kruskal-Wallis Test were used to analyze the potential impacts of report appropriateness. Results Totally 609 (54.38%)laboratories submitted the survey results. The sigma metrics of six quality indicators on report appropriateness were more than 4. The main reason for report delay was equipment failure. Group comparison suggested that the report appropriateness of laboratories in tertiary-A hospitals and accredited by ISO 15189 werebetter. Report appropriateness with electronic request, electronic form and electronic transmission were superior than that inother ways. Conclusions Report appropriateness in China differs from laboratory to laboratory. Laboratories should develop emergency action plan in case the instrument breaks down and strengthen information technology. Long-term internal quality control and external quality assessment scheme are very meaningful to identify the insufficient performance and improve laboratory quality. (Chin J Lab Med, 2015, 38: 632-636) Key words: Hematologic tests; Quality control; Laboratories, hospital; Laboratory proficiency testing; Clinical laboratory information systems

Proficiency testing for the detection of anti-citrullinated protein antibody in China

BackgroundAnti-citrullinated protein antibodies (ACPAs) are important for the detection of rheumatoid arthritis (RA). There are many laboratories to detect it in their routine work, but their performance is not displayed in China. To examine the performance of ACPA assays from all laboratories, it is necessary to organize a laboratory proficiency test (PT). MethodsA panel of 5 samples, including 4 positive and 1 negative, was produced by the National Center for Clinical Laboratories, using serum derived from patients, then distributed to 271 clinical laboratories. Quantitative and qualitative results reported by the participating laboratories were compared. ResultsOverall, 80.97% (200/247) of the laboratories had eligible PT scores. Of the kits used, most ELISA and chemiluminescence kits had a high sensitivity and specificity. Regarding intra-assay discrepancy, the Roche and Abbott kit had a better variable coefficient. The ratios of the quantitative results to the kit-specific cut-off values were similar. ConclusionPerformance varied between laboratories. Reagents and methods are the most important factors. Other factors may affect the intra-assay discrepancy. The similar mean of ratios of the quantitative results to the kit-assigned cut-offs suggests that a national criterion is requisite. It is necessary to organize a PT to identify performances of different laboratories.

Proficiency testing carried out by the European Union Reference Laboratory for Parasites

The European Union Reference Laboratory for Parasites (EURLP) organises proficiency testing (PT) for the National Reference Laboratories for Parasites (NRLs) of the member states and for public and private laboratories performing official controls in European and extra-EU countries, in order to assess their competence and to improve laboratory performance. Since its appointment in July 2006, the EURLP organised almost 50 PTs on different methods to detect and identify foodborne parasites. According to the Commission Regulation (EC) 2075/2005, all animals which are potential carriers of Trichinella spp. larvae, shall be tested at the slaughterhouse by one of the methods reported in the Regulation 2075/2005. The EURLP organised eight PTs (once a year) on detection of Trichinella larvae in a panel of meat balls, made by minced pork or horse meat spiked with Trichinella larvae. Moreover, PTs on the identification of Trichinella parasites by molecular methods were organised; samples consisted of Trichinella larvae preserved in 95 % ethanol. The EURLP organised PTs to test the competence of NRLs to detect Anisakidae larvae in fish fillets. PTs were also organised to test the competence of NRLs to detect Echinococcus sp. worms or their parts in the intestinal mucosa of canids, definitive hosts of these parasites. All PTs were qualitatively evaluated; a quantitative evaluation was also performed, when appropriate, in order to provide participants with a useful tool to improve their performance.

Suggestions for analytical performance verification and experimental designs for clinical laboratory tests

The analytical performance verification of clinical laboratory tests plays the key role in the new edition of laboratory quality and Competence Accreditation (ISO15189: 2012). This review, which is based on the new edition of accreditation criteria and Guidance on the Application of Accreditation Criteria for the Medical Laboratory Quality and Competence in the Field of Clinical Chemistry , and with the reference of documents issued from Clinical and Laboratory Standards Institute(CLSI), will give some requirements of analytical performance verification and experimental designs for clinical laboratory tests.(Chin J Lab Med, 2015, 38: 428-430) Key words: Clinical laboratory techniques; Laboratory proficiency testing; Research design

Quality assurance of clinical biochemistry testing: a mualti-center study based reference interval for clinical chemistry tests in the Chinese population

Objective To verify and monitor the performance of accuracy, precision and comparability of 26 clinical biochemical analytes (29 methods) in the six centers involved in multi-centers reference intervals research, and to ensure the reliability of theirmeasurement results. Methods During the period of the systems evaluating, two levels of commercial quality control materials and fresh frozen human serum reference materials were applied to verify the performance of inter-laboratory precision and accuracy of analysis systems. During the period of samples testing, the commercial quality control materials were measured whenever samples were analysed, the fresh frozen serum reference materials were measured once a month. The coefficient of variations (CVs), bias and total errors were calculated to assess the precision, accuracy and comparability. Results Verification of precision and accuracy: (1) the ranges of CVs of 29 methods in the six laboratory laboratories were 0.4%-6.0%, the CVs of all 29 methods met the criterion .(2) The overall average bias of the analysis systems of 21 analytes (24 methods) ranged from -5.15% (ALT) to 4.46% (Ur). Among 24 methods the overall average bias of TP, Glu-GOD, Ur, Cl, Ca exceeded the acceptable range. The quality assessment during the period of samples testing: (1) The overall average bias ranged from -1.95%(Ca) to 2.92%(Ur), median 1.26%, they all met the requirements of relevant standards.(2)When commercial control materials were tested, the requirements of CVs were fulfilled for most methods in the six laboratories, and the CVs of TP, Alb, Cl, Ca exceeded the acceptable range.The overall average TE of all methods met the quality specification for the C-N controls material. For the C-P control material, only the overall average TE of TP (5.05%) exceeded thearceptable range while the other methods met the requirement in criterion. Conclusions The performance of precision and accuracy of the analysis systems used in the six laboratories passed the verification. During the period of sample testing, the performance of precision and accuracy of the most methods in the 6 laboratories met the requirements of quality specifications, and the overall performance was good. Because of the limitation of current technology the performance of some methods didn't fulfill the requirement of specifications, and need to be improved.(Chin J Lab Med, 2015, 38: 301-305) Key words: Reference values; Quality assurance, health care; Clinical chemistry tests; Laboratory proficiency testing