Proficiency Testing Schemes Research Articles

Ensuring Quality and Consistency in OPC-53 Cement Testing: A Comprehensive Proficiency Testing Evaluation

The proficiency testing (PT) program is a critical part of quality assurance in laboratories, especially within industries like construction where cement testing is essential. This study provides a comprehensive evaluation of the fifth PT scheme for Ordinary Portland Cement (OPC) grade 53, conducted by the Nodal Laboratory. The key parameters assessed in this program were standard consistency, compressive strength, and soundness using the Le-Chatelier method. Twenty-four laboratories participated, and their performance was analyzed using advanced statistical methods, adhering to ISO 17043:2010 and ISO 13528:2015 standards. The results showed that most laboratories performed satisfactorily, with only one outlier identified in the soundness test. This paper covers all aspects of the PT program, from sample preparation to the distribution of materials, as well as the homogeneity and stability tests conducted on the samples. Statistical evaluation was carried out using Z-scores, which allowed the laboratories to be ranked according to their performance in each parameter. This method highlights discrepancies and provides a clear framework for participating laboratories to improve their testing procedures. Proficiency testing is essential for maintaining high standards in laboratory performance. It helps standardize testing methods across multiple laboratories, ensuring that OPC-53 cement meets strict quality and performance specifications. The program enables laboratories to identify performance gaps and take corrective actions, ensuring the reliability and accuracy of results. Participation in PT programs is a step toward continuous improvement, keeping laboratories aligned with international standards, ultimately benefiting the broader construction industry by ensuring the structural integrity of buildings and infrastructure. This study underscores the importance of regular PT participation. It not only provides a benchmark for laboratory performance but also ensures compliance with ISO standards. This fosters the consistent quality of cement used in large-scale construction, reducing the risk of structural failures and contributing to long-term safety and durability. The findings demonstrate the positive impact of PT programs on overall testing accuracy and laboratory reliability, emphasizing their role in advancing best practices in the construction industry.

Personalization of pharmacotherapy with sirolimus based on volumetric absorptive microsampling (VAMS) in pediatric renal transplant recipients-from LC-MS/MS method validation to clinical application.

The benefits of pharmacotherapy with sirolimus (SIR) in pediatric transplant recipients are well established. Traditionally, whole blood samples have been used to measure SIR concentrations. Volumetric Absorptive Microsampling (VAMS) is an alternative sampling strategy suitable for Therapeutic Drug Monitoring (TDM). In this study, we developed and validated two liquid chromatography-tandem mass spectrometry (LC-MS/MS) methods for determining SIR concentrations in whole blood (WB) and capillary whole blood samples collected using a VAMS-Mitra™ device. We used protein precipitation during WB sample preparation and dispersive liquid-liquid microextraction (DLLME) with methyl tert-butyl ether for VAMS sample preparation to optimise the analyte extraction process. The described validation protocols were cross-validated, confirming the equivalence of the whole-blood and VAMS-based methods. Furthermore, the developed methods were evaluated in two three-level rounds of an external proficiency-testing scheme. The analytical methods were successfully validated within the calibration range of SIR (0.5-60 ng/ml). The validation parameters met the European Medicines Agency (EMA) and the International Association of Therapeutic Drug Monitoring and Clinical Toxicology (IATDM&CT) acceptance criteria. No hematocrit (tested in the range of 24.3-64.1%), matrix, or carry-over effects were observed. Cross-validation confirmed the interchangeability between VAMS-LC-MS/MS and WB-LC-MS/MS methods. The developed methods were successfully implemented for SIR determination in 140 clinical samples (70 each of WB and VAMS) from pediatric renal transplant recipients, demonstrating their practicality and reliability. The VAMS-based method has been rigorously tested and is clinically equivalent to the reference WB-LC-MS/MS method. Additionally, clinical validation confirmed the utility of the presented methods for TDM of the SIR in the pediatric population after renal transplantation.

The 2023 National Proficiency Test for molecular detection of shrimp infectious myonecrosis virus (IMNV) in China

Infectious myonecrosis virus (IMNV), an emerging virus that can cause severe viral disease in penaeid shrimp, was first confirmed to have spread to China in 2020. In order to standardize diagnostic procedures and reliable detection capability, and to evaluate the performances of aquatic clinical diagnostic laboratories, the competent authority has launched a proficiency test (PT) scheme for the molecular detection of IMNV in China from the year of 2023. In the ring test of IMNV-PT 2023, five tissue samples containing different concentrations of IMNV were provided as a panel of test samples. A total of 68 laboratories participated in the PT test of qualitative and quantitative analysis of the five samples using standard molecular assays. The results showed that 92.65 % (63/68) of the participants correctly reported all samples in the panel using Real-time reverse transcription PCR and 62 participants achieved satisfactory results, one participant using conventional PCR and four participants had not completed the test. Out of the 62 participants in the z-scores analysis, 88.71 % (55/62) achieved acceptable ZB-scores, with two outlier laboratories and five laboratories being questionable. Additionally, 98.39 % (61/62) achieved ZW-scores, with only one laboratory being questionable. Furthermore, the national PT conducted in the present study proved to be an effective tool for evaluating laboratory performance in IMNV molecular testing. This assessment can aid in improving the capabilities of IMNV molecular testing of the participating laboratories, and also provided technical supporting to enhance the national response to IMN outbreaks.

Challenges and improvements in HER2 scoring and histologic evaluation: insights from a national proficiency testing scheme for breast cancer diagnosis in China

BackgroundIn 2022, our team launched the pioneering national proficiency testing (PT) scheme for the pathological diagnosis of breast cancer, rapidly establishing its credibility throughout China. Aiming to continuously monitor and improve the proficiency of Chinese pathologists in breast pathology, the second round of the PT scheme was initiated in 2023, which will expand the number of participating institutions, and will conduct a nationwide investigation into the interpretation of HER2 0, 1+, and 2+/FISH- categories in China.MethodsThe methodology employed in the current round of PT scheme closely mirrors that of the preceding cycle in 2022, which is designed and implemented according to the “Conformity assessment—General requirements for proficiency testing”(GB/T27043—2012/ISO/IEC 17043:2010). More importantly, we utilized a statistics-based method to generate assigned values to enhance their robustness and credibility.ResultsThe final PT results, published on the website of the National Quality Control Center for Cancer (http://117.133.40.88:3927), showed that all participants passed the testing. However, a few institutions demonstrated systemic biases in scoring HER2 0, 1+, and 2+/FISH- with accuracy levels below 59%, considered unsatisfactory. Especially, the concordance rate for HER2 0 cases was only 78.1%, indicating challenges in distinguishing HER2 0 from low HER2 expression. Meanwhile, areas for histologic type and grade interpretation improvement were also noted.ConclusionsOur PT scheme demonstrated high proficiency in diagnosing breast cancer in China. But it also identified systemic biases in scoring HER2 0, 1+, and 2+/FISH- at some institutions. More importantly, our study highlighted challenges in the evaluation at the extreme lower end of the HER2 staining spectrum, a crucial area for further research. Meanwhile, it also revealed the need for improvements in interpreting histologic types and grades. These findings strengthened the importance of robust quality assurance mechanisms, like the nationwide PT scheme conducted in this study, to maintain high diagnostic standards and identify areas requiring further training and enhancement.

Overview of proficiency testing results for the invivo determination of sun protection factor.

A sunscreen product is allowed to be marketed if a protection is provided against ultraviolets (UV) including UVA rays and UVB rays expressed by the sun protection factor (SPF). UVB is radiation that is in the region of the ultraviolet spectrum which extends from about 290 to 320 nm in wavelength and that is primarily responsible for sunburn, ageing of the skin, and the development of skin cancer. Thus, since April 2009, the Bureau Interprofessionnel d'Etudes Analytiques (BIPEA) set up a proficiency testing scheme (PTS) for the determination of SPF invivo of sunscreen products according to ISO 24444 standard [Cosmetics - Sun protection test methods - in vivo determination of the sun protection factor (SPF)] to evaluate the analytical performances of laboratories on these analyses. This PTS gathers twenty-six laboratories around the world with one trial a year. For each test, the statistical treatment of the data is performed according to ISO 13528 standard [Statistical methods for use in proficiency testing by interlaboratory comparison]. The assigned and tolerance values are calculated from the participants' data and the performances of the laboratories are evaluated individually and collectively according to ISO 17043 standard [Conformity assessment - General requirements for proficiency testing]. This paper presents the design of the PT program, its development, and an attentive analysis of laboratories results, which highlight the global performances obtained by laboratories on this type of analysis. The evaluation of the results shows, in fact, a relatively constant dispersion of data since the implementation of the PT program (variability between 10% and 50%).

A novel approach to therapeutic drug monitoring of Ciclosporin in pediatric renal transplant recipients using volumetric absorptive microsampling (VAMS) – Teaching old dog new tricks

Background and aimsCiclosporin (CSA) is an immunosuppressive agent that requires therapeutic drug monitoring (TDM). High partitioning in erythrocytes indicates that whole blood (WB) is a suitable matrix for CSA determination. Alternative sampling strategies, such as volumetric absorptive microsampling (VAMS), are novel possibilities for blood collection during TDM for various analytes, including immunosuppressants. This technique is attractive for vulnerable pediatric patients, including home-based self-sampling, remote therapy, and adherence control. Materials and methodsThis study aimed to develop and validate a new method for CSA determination based on liquid chromatography-tandem mass spectrometry (LC-MS/MS) of WB and VAMS samples. Additionally, these methods were applied for CSA determination in clinical samples from pediatric transplant recipients. A strong point of this study is the assessment of an external proficiency testing scheme. ResultsBoth methods were successfully validated within the 1–2000 ng/mL calibration range, with LOD 0.5 and 1 ng/mL for WB and VAMS methods, respectively. All the validation parameters fulfilled the international acceptance criteria for bioanalytical methods. Cross-validation confirmed the interchangeability of the LC-MS/MS method developed in this study. ConclusionThis study developed and validated novel methods for CSA determination in whole blood and VAMS using LC-MS/MS. Clinical validation and proficiency testing confirmed their utility in routine clinical practice.

Indonesian experience in providing accuracy-based proficiency testing scheme using metrologically traceable reference values for elements mass fraction in drinking water

Indonesian experience in providing accuracy-based proficiency testing scheme using metrologically traceable reference values for elements mass fraction in drinking water

Carbon monoxide proficiency testing scheme with metrological traceability

Carbon monoxide proficiency testing scheme with metrological traceability

Certification of Meissen Granite IAG GMN‐1 Using the GeoPT Proficiency Testing Certification Protocol

Following a full assessment of the GeoPT proficiency testing scheme against the recommendations in ISO Guide 35:2017 for the use of proficiency testing in the certification of reference materials, this paper presents the first application of the GeoPT certification protocol in the characterisation of a new geochemical CRM, IAG GMN‐1, Meissen Granite. This protocol is applied to the measurement results reported in Round 51 of the GeoPT programme in which the candidate CRM was used as the test material, together with an established CRM (CGL 008 MGT‐1 Granite) to provide validation of the results. Following the presentation of mineralogy, grain‐size analysis and homogeneity testing data for IAG GMN‐1, certified values for nine major elements and thirty‐nine trace elements are reported.

The multifaceted impact of ISO/IEC 17025 accreditation: a sector-specific analysis in civil engineering testing and calibration laboratories

PurposeThis study aims to dissect the multifaceted impact of ISO/IEC 17025 accreditation, specifically within civil engineering testing and calibration laboratories. To achieve this, it intends to explore several key objectives: identifying the prominent benefits of accreditation to laboratory performance, understanding the advantages conferred through participation in proficiency testing schemes, assessing the role of accreditation in enhancing laboratory competitiveness, examining the primary challenges encountered during the accreditation process, investigating any discernible adverse effects of accreditation on laboratory performance and evaluating whether the financial cost of accreditation justifies the resultant profitability.Design/methodology/approachThis study employs a qualitative approach through semi-structured interviews with 23 industry professionals—including technical managers, quality managers, external auditors and clients. Thematic analysis, guided by Braun and Clarke’s six-stage paradigm, was utilized to interpret the data, ensuring a comprehensive understanding of the accreditation’s impact.FindingsFindings reveal that accreditation significantly enhances operational processes, fosters quality awareness and facilitates continuous improvement, contributing to greater client satisfaction. In addition, standardized operations and rigorous quality controls further result in enhanced performance metrics, such as staff capability and measurement accuracy. However, the study also uncovers the challenges of accreditation, including high resource costs and bureaucratic hurdles that can inhibit innovation and slow routine operations. Importantly, the research underscores that the impact of accreditation on profitability is not universal, but contingent upon various factors like sector-specific regulations and market demand. The study also highlights sector-specific variations in the role of accreditation as a marketing tool and differing perceptions of its value among clients. It further emphasizes the psychological stress of high-stakes evaluations during audits.Originality/valueThis study represents the first in-depth investigation into the impact of ISO/IEC 17025 accreditation on civil engineering testing and calibration laboratories, directly contributing to the enhancement of their quality and operational standards. Providing actionable insights for laboratories, it underscores the importance of weighing accreditation costs and benefits and the necessity for a tailored approach to the unique market and regulatory landscapes they operate in.

Predicting flow cytometry crossmatch results from single-antigen bead testing.

The aim of this study was to devise an algorithm that would predict flow cytometry crossmatch (FCXM) results using single-antigen bead (SAB) mean fluorescent intensity (MFI) levels using samples received through the National External Quality Assurance Scheme (NEQAS) 2B external proficiency testing scheme between 2019 and 2023. A total of 159 serum samples were retrospectively screened using LABScreen Single Antigen Class I and II (SAB), and 40 peripheral blood samples were human leucocyte antigen (HLA) typed with LABType SSO. Donor-specific antibodies were identified for each cell-serum combination tested, and cumulative MFI values were calculated for each test before correlating the screening result with the consensus crossmatch results for this scheme. HLA Class I MFIs were combined to predict the T cell crossmatch. For the B cell crossmatch prediction, two options were considered: (i) HLA Class II MFI values alone and (ii) HLA Class I+Class II MFIs. Receiver operating characteristic analysis was carried out to identify the combined MFI threshold that predicted NEQAS consensus results with the greatest sensitivity and specificity. HLA Class I combined MFI >5000 predicted T cell crossmatch results with 96% sensitivity, 100% specificity, 100% positive predictive value (PPV) and 92% negative predictive value (NPV). For B cell results, HLA Class I+Class II combined MFIs >11,000 gave the best model, showing 97% sensitivity, 82% specificity, 96% PPV and 85% NPV. However, for samples with only HLA Class II sensitization, combined MFIs >13,000 improved the B cell crossmatch predictions: 92% sensitivity, 95% specificity, 96% PPV and 91% NPV. Using this model, combined MFI can be used to predict the immunological risk posed by donor-specific antibodies when it is not possible to carry out an FCXM.

S-score: a new score for binary qualitative proficiency testing schemes interpretable as the z-score

S-score: a new score for binary qualitative proficiency testing schemes interpretable as the z-score

Current status and perspectives of the quality system in histocompatibility laboratories in Poland.

Allogeneic transplantation is a multi-step process involving many clinicians and laboratory personnel working together to achieve a common goal-to maximize the recipients' chance of survival and to improve their quality of life. One of the key elements of the process is to ensure high quality, accuracy, and reliability of histocompatibility testing. This manuscript presents: the development and organizational principles of the national system of supervision and control of histocompatibility laboratories in Poland, problems faced by these laboratories, availabe proficiency testing schemes, as well as suggestions and prospects for the future raised by members of the Polish histocompatibility community.

Proficiency testing of diagnosis in histopathology and immunohistochemistry of breast pathology in China: results from a pilot work of National Single Disease Quality Control Program for breast cancer

AimPathologists are currently supposed to be aware of both domestic and international guidelines for breast cancer diagnosis, but it is unclear how successfully these guidelines have been integrated into routine clinical practice in China. Thus, this national proficiency testing (PT) scheme for breast pathology was set up to conduct a baseline assessment of the diagnostic capability of pathologists in China.MethodsThis national PT plan is designed and implemented according to the “Conformity assessment—General requirements for proficiency testing” (GB/T27043—2012/ISO/IEC 17043:2010). Five cases of breast cancer with six key items, including histologic type, grade, ER, PR, HER2, and Ki67, were selected for testing among 96 participants. The final PT results were published on the website of the National Quality Control Center for Cancer (http://117.133.40.88:3927/cn/col22/362).ResultsOur study demonstrated that the median PT score was 89.5 (54–100). Two institutions with scores < 67 were deemed unacceptable. The accuracy of histologic type, ER, PR, HER2, and Ki67 was satisfactory (all > 86%). However, the histologic grade showed low accuracy (74.0%). The unacceptable results mainly included incorrect evaluation of histologic grade (36.7%), inaccurate evaluation of ER/PR/HER2/Ki67 (28.2%), incorrect identification of C-AD as IBC-NST (15.7%), inappropriate use of 1+/2+/3+ rather than staining percentage for ER/PR (6.1%), misclassification of ER/PR < 1% weak expression as positive staining (1.4%), and no evaluation of histologic grade in ILC, MC, and IMC (5.8%).Conclusionsour nationwide PT program exhibited a satisfactory baseline assessment of the diagnostic capability of pathologists in China. More importantly, we identify some areas for further improvement.

Evaluation of five multisteroid LC‒MS/MS methods used for routine clinical analysis: comparable performance was obtained for nine analytes.

A mass spectrometry (LC‒MS/MS)-based interlaboratory comparison study was performed for nine steroid analytes with five participating laboratories. The sample set contained 40 pooled samples of human serum generated from preanalyzed leftovers. To obtain a well-balanced distribution across reference intervals of each steroid, the leftovers first underwent a targeted mixing step. All participants measured a sample set once using their own multianalyte protocols and calibrators. Four participants used in-house developed measurement platforms, including IVD-CE certified calibrators, which were used by three participants; the 5th lab used the whole LC‒MS kit from an IVD manufacturer. All labs reported results for 17-hydroxyprogesterone, androstenedione, cortisol, and testosterone, and four labs reported results for 11-deoxycortisol, corticosterone, cortisone, dehydroepiandrosterone sulfate (DHEAS), and progesterone. Good or acceptable overall comparability was found in Bland‒Altman and Passing‒Bablok analyses. Mean bias against the overall mean remained less than ±10 % except for DHEAS, androstenedione, and progesterone at one site and for cortisol and corticosterone at two sites (max.-18.9 % for androstenedione). The main analytical problems unraveled by this study included a bias not previously identified in proficiency testing, operator errors, non-supported matrix types and higher inaccuracy and imprecision at lower ends of measuring intervals. This study shows that intermethod comparison is essential for monitoring the validity of an assay and should serve as an example of how external quality assessment could work in addition to organized proficiency testing schemes.

Inter-laboratory comparison of a digital multimeter measurement in Turkey

The standard ISO/IEC 17043:2023 specifies the general requirements for proficiency testing providers and covers the development, operation, and reporting of proficiency testing schemes. The standard aims to ensure that the measurement results obtained by different laboratories are comparable and traceable to international measurement standards. Inter-laboratory comparisons are still rare in the meteorological services network of calibration laboratories, and there are not enough bodies accredited with the ISO/IEC 17043:2023 standard in Turkey. The existing inter-laboratory comparison measurements do not fully comply with the requirements of ISO/IEC 17043:2023 and are not compatible with the measurement capabilities and scopes of the laboratories, leading to difficulties when comparing meteorological data from different laboratories. This article presents a case study of a digital multimeter interlaboratory comparison measurement in accordance with the ISO/IEC 17043:2023 standard. The results obtained were analysed using statistical methods (En score) and compared to the reference values provided by a secondary accredited calibration laboratory. The analysis showed that the measurement results obtained by the participants were consistent and generally within the acceptable range of En. The case study presented in this paper demonstrates the effectiveness of the standard in ensuring reliable measurement results in a practical setting.

Matrix Effect Evaluation in GC/MS-MS Analysis of Multiple Pesticide Residues in Selected Food Matrices

Multi-analyte methods based on QuEChERS sample preparation and chromatography/mass spectrometry determination are indispensable in monitoring pesticide residues in the feed and food chain. QuEChERS method, even though perceived as convenient and generic, can contribute to sample matrix constituents’ introduction to the measuring system and possibly affect analytical results. In this study, matrix effects (ME) were investigated in four food matrices of plant origin (apples, grapes, spelt kernels, and sunflower seeds) during GC-MS/MS analysis of &gt;200 pesticide residues using QuEChERS sample preparation. Data analysis revealed considerable analyte signal enhancement and suppression: strong enhancement was observed for the majority of analytes in two matrices within the commodity groups with high water content—apples, and high acid and water content—grapes (73.9% MES and 72.5% MEA, and 77.7% MES and 74.9% MEA, respectively), while strong suppression was observed for matrices within the commodity groups with high starch/protein content and low water and fat content—spelt kernels, and high oil content and very low water content—sunflower seeds (82.1% MES and 82.6% MEA, and 65.2% MES and 70.0% MEA, respectively). Although strong matrix effects were the most common for all investigated matrices, the use of matrix-matched calibration for each sample type enabled satisfactory method performance, i.e., recoveries for the majority of analytes (up to roughly 90%, depending on the fortification level and matrix type), which was also externally confirmed through participation in proficiency testing schemes for relevant food commodity groups with the achieved z-scores within acceptable range ≤ |2|.

Proficiency testing schemes in laboratory lessons: a useful and powerful educational tool in bioscience studies

ABSTRACT Bias assessment (systematic errors) is fundamental in industry and service laboratories, where reliable results must be obtained to give correct answers to specific problems. Therefore, knowledge and practice in quality methodologies is of fundamental importance for students. Unfortunately, laboratory lessons often focus on connecting theory and practice without developing the quality assurance skills that employers consider to be useful. Here, an external quality methodology based on proficiency testing schemes has been developed to introduce students to the methodologies and skills that are required to detect and find the source of biased results in the laboratory. It has been found that a large percentage of results obtained during laboratory lessons are in fact biased. The new methodology obliges students to practise how to detect biased results and, specially, the critical thinking skills that are needed to reveal the sources of bias in the laboratory. In the case study evaluated here, the application of the proposed methodology allowed students to detect the source of their biased result in 95% of the cases. Errors found were mainly due to personnel errors, as a consequence of deficits in basic hands-on skills and calculation errors.

Development of a national proficiency test for SARS-CoV-2 detection by PCR in Colombia.

Proficiency testing (PT) is a tool for ensuring the validity of results of testing laboratories and is essential when laboratories are working with assays authorised for emergency use or implementing novel techniques for detecting emerging pathogens. In collaboration with the National Health Institute of Colombia and with international support, we developed a qualitative PT for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) by reverse transcription polymerase chain reaction (RT-PCR). A proficiency test item (PTI) based on reference material (research grade) produced by the National Institute of Standards and Technologies (NIST) was prepared and characterised using three positive samples with varying concentrations of SARS-CoV-2 ribonucleic acid (RNA) and two negative (control) samples. Tests were distributed to 121 laboratories across the national network of public health laboratories in Colombia. Positive samples had varying concentrations of SARS-CoV-2 RNA and were quantified by digital PCR (RT-ddPCR) assays for the E gene of SARS-CoV-2. We tested the ability of laboratories to detect low and high levels of viral RNA using samples with SARS-CoV-2 RNA concentrations of 1417 ± 216, 146 ± 28, and 14 ± 10 copies /uL (expanded uncertainty, k = 2, 95% confidence level) We also performed a semiquantitative analysis of instrumental responses (Ct values) reported by participating laboratories and homogeneity, stability, and characterisation studies of the produced materials to determine the adequacy of these materials and methods for use in the qualitative PT scheme. The PT evaluated reports for individual target genes from each laboratory; 98.3% of laboratories had satisfactory performance and the remaining 1.7% of laboratories had unsatisfactory performance for the detection of at least one of the reported genes. This PT scheme identified the potential metrological weaknesses of laboratories in the detection of SARS-CoV-2 by RT-PCR and may facilitate improvements in the quality of measurements from the perspective of public health surveillance.

The history and evolution of HLA typing external proficiency testing schemes in UK NEQAS for H&I.

The UK National External Quality Assessment Service (NEQAS) provide an external proficiency testing (EPT) service for clinical laboratories. UK NEQAS for Histocompatibility and Immunogenetics (H&I) has been providing EPT schemes for over 45years and has grown during this time to provide 19 EPT schemes. Accurate human leucocyte antigen (HLA) typing is critical to support safe clinical services, including transplantation, therefore high quality, relevant EPT schemes are required as part of a laboratory's quality assurance. This article reviews the development of the HLA typing EPT schemes, from the first HLA phenotyping scheme in 1975, via the first HLA genotyping scheme in 1992, through to the introduction in 2017 of HLA third field assessment results from next-generation sequencing technology. In addition, the introduction of EPT schemes to cover HLA associated diseases and pharmacogenetic reactions, including HLA-B27, HLA*B*57:01 and HLA-DQ for coeliac disease are discussed. The accuracy of laboratory EPT results for HLA phenotyping are >96% (2018-2022), HLA genotyping >99% (2020-2022), HLA-B27 testing >99% (2018-2022) and B*57:01 testing >99% (2017-2022). However, for HLA genotyping for coeliac disease 22%-46% of laboratories made errors in 2020-2022. On investigation, the high rate of unsatisfactory performance was attributed to laboratories lacking specific knowledge to interpret HLA genotyping results and accurately report HLA types for coeliac disease. A misleading commercial kit insert was also identified. The assessment of scheme results has uncovered several issues which have been addressed with the intention of educating participants and improving clinical services. The UK NEQAS for H&I EPT schemes have evolved over the past four decades to reflect changes in HLA typing technology, laboratory clinical practice and to cover post-analytical interpretative elements of HLA typing.