Quality Assessment Scheme Research Articles

The EuroFlow PIDOT external quality assurance scheme: enhancing laboratory performance evaluation in immunophenotyping of rare lymphoid immunodeficiencies.

The development of External Quality Assessment Schemes (EQAS) for clinical flow cytometry (FCM) is challenging in the context of rare (immunological) diseases. Here, we introduce a novel EQAS monitoring the primary immunodeficiency Orientation Tube (PIDOT), developed by EuroFlow, in both a 'wet' and 'dry' format. This EQAS provides feedback on the quality of individual laboratories (i.e.,accuracy, reproducibility and result interpretation), while eliminating the need for sample distribution. In the wet format, marker staining intensities (MedFIs) within landmark cell populations in PIDOT analysis performed on locally collected healthy control (HC) samples, were compared to EQAS targets. In the dry format, participants analyzed centrally distributed PIDOT flow cytometry data (n=10). We report the results of six EQAS rounds across 20 laboratories in 11 countries. The wet format (212 HC samples) demonstrated consistent technical performance among laboratories (median %rCV on MedFIs=34.5 %; average failure rate 17.3 %) and showed improvement upon repeated participation. The dry format demonstrated effective proficiency of participants in cell count enumeration (range %rCVs 3.1-7.1 % for the major lymphoid subsets), and in identifying lymphoid abnormalities (79.3 % alignment with reference). The PIDOT-EQAS allows laboratories, adhering to the standardized EuroFlow approach, to monitor interlaboratory variations without the need for sample distribution, and provides them educational support to recognize rare clinically relevant immunophenotypic patterns of primary immunodeficiencies (PID). This EQAS contributes to quality improvement of PID diagnostics and can serve as an example for future flow cytometry EQAS in the context of rare diseases.

Clinical application of an optimized reference measurement procedure for serum digoxin using bracketing calibration method by ID-LC-MS/MS.

Digoxin, a cardiac glycoside, is widely used in the treatment of cardiovascular diseases. Due to its narrow therapeutic range, precise monitoring of its blood concentration is essential. Areference measurement procedure (RMP) is pivotal for ensuring result accuracy and comparability. The RMP for serum digoxin by ID-LC-MS/MS was optimized with sample pre-treatment and detection processes, and the bracketing calibration method was used, which facilitates more accurate measurement, especially for extreme concentrations. The performance of this optimized RMP was thoroughly evaluated. The limit of detection (LoD) was 0.05 ng/mL (0.06 nmol/L) and the lowest limit of quantification (LLoQ) was 0.10 ng/mL (0.13 nmol/L). The intra- and inter-assay imprecisions were 2.24%, 2.51%, 1.40% and 1.72%, 1.65%, 0.97% at 0.5, 2.0, 5.0 ng/mL, respectively. Recoveries were 99.63 to 101.42% and thelinear response ranged from 0.1 to 10.0 ng/mL. The relative bias was 0.41% and 2.00% of our results compared with the median of all participating reference laboratories for IFCC-RELA (External Quality Assessment Scheme for Reference Laboratories in Laboratory Medicine) 2023A and 2023B. The uncertainty, calibration and measurement capability (CMC) of this method were also evaluated. The optimized RMP was applied in the Trueness Verification Plan of Southern China, which indicates significant differences among clinical systems, highlighting the need for standardization efforts. In addition, two commonly used clinical systems which employed immunoassay methods were compared with this optimized RMP, and 26 individual serum samples were analyzed. The good correlations indicate the feasibility of standardization for serum digoxin. The optimized RMP serves as an accurate reference baseline for routine methods, aiming to enhance the accuracy and precision of measurements in clinical laboratories.

Analytical evaluation of eight qualitative FIT for haemoglobin products, for professional use in the UK.

Qualitative faecal immunochemical tests for haemoglobin (FIT), for triaging for colorectal cancer investigations, are available for professional use. The aim was to evaluate these lateral flow tests. No previous analytical evaluations have been published. Analytical sensitivity (AS) was assessed using samples spanning manufacturers' quoted AS, concurrently with the quantitative OC-SENSOR PLEDIA, using Hb-spiked samples in manufacturers' buffer (n≥5;≤9-99 ng Hb/mL buffer), Hb-spiked faeces (n=6;<2-34 µg Hb/g faeces) and natural faeces (n=17;<2-82 μg/g); concentrations for 50 %/100 % Hb-detected were compared with quoted AS. Compatibility with two external quality assessment schemes (EQAS) (n=9; 3-96 μg/g) and prozone compared with manufacturers limits (n=9; 2,500-10,000,000 ng/mL) were tested. Ease-of-use by five healthcare personnel was assessed. Seven products showed lower AS (ng/mL) than manufacturers quoted using Hb-spiked aqueous samples compared with OC-SENSOR, one was equivocal; six manufacturers quoted AS in µg/g, five showed lower AS using Hb-spiked faeces. Results were similar but less consistent for natural faeces. Result lines for low concentrations can be faint and open to interpretation. Results were consistent with manufacturers quoted prozone limits. Results were consistent for seven products for two EQAS. The ease-of-use was 68.5-85.6 %; products with lower scores could be improved with better instructions and sample bottles. AS was lower for seven products (aqueous samples) and five products (aqueous/faecal samples) and prozone consistent with manufacturers expected concentrations, compared with OC-SENSOR. EQAS results were mostly consistent with expected results; products can be used by healthcare professionals, though some manufacturer improvements could be made.

A-135 Assessment of Inter-Laboratory Variation in Biochemistry Parameters in Mongolian Clinical Laboratories: A Twelve-Year Analysis

Abstract Background External quality assessment (EQA) is essential for evaluating the performance of clinical laboratories and improving the quality of their analytical procedures. The Mongolian External Quality Assessment Scheme (MEQAS) has been established by organizations under the Ministry of Health to fulfill this purpose. The aim of this study is to provide a comprehensive summary of the inter-laboratory variation in biochemistry parameters among laboratories in Mongolia over a twelve-year period. Methods Three types of control materials were utilized: QAP-Trol Normal and Pathological levels, manufactured by Sysmex, and Pooled serum, prepared by combining leftover serum of patients. Samples were distributed semi-annually to laboratories, with participants measuring them promptly within three days. Results for 23 biochemistry parameters were submitted within a week via the “SmartEqas” software, enabling for analysis based on method and analyzer, and calculating standard deviation index (SDI), coefficient of variation (CV), and bias percentage (Bias%). Results In comparing the initial and most recent surveys, the number of participants has increased by nearly four times, rising from 55 to 217. Notably, the proportion of fully automatic users surged from 23.6% to 86.6%, a trend attributed to the establishment of numerous new laboratories and a growing recognition of the importance of EQA. Changes in the inter-laboratory coefficient of variation (CV) for each parameter were assessed from the initial to the recent period by calculating the mean of changes. In the recent assessments, CVs decreased to less than 10% for 14 parameters, including AST, ALT, UN, CRE, GLU, and others. Certain parameters, such as K, GLU, and Urea, exhibited markedly reduced variation from 16.3%, 12.1%, and 22.2% to 2.9%, 7.4%, and 9.3%, respectively. Conversely, some parameters, including LD (L-P), GGT, AMY (1), ALP (2), UA, TBIL, DBIL, FE, and MG, displayed gradual reductions in CVs to 10-20% compared to the initial period. In contrast, the coefficient of variation (CV) for four parameters: LD (P-L), AMY (2), ALP (3), and ALP (4), has not shown significant decreases and remains high, exceeding 20%. Conclusions Despite participation not being mandatory, laboratories in Mongolia exhibit a strong willingness to engage in the assessment process. The implementation of MEQAS has yielded tangible benefits, a reduction in inter-laboratory variation for most biochemistry parameters, with some achieving international level. While this improvement can be attributed to the streamlining of measurement methods, similar to outcomes observed in other countries, it is important to acknowledge the persistence of random and systematic errors. However, it is worth noting that certain parameters still exhibit higher CVs compared to similar studies. This discrepancy may be attributed to the inherent variation in enzymes among different methods and manufacturers. Hence, there is a clear need for continuous improvement measures and knowledge-sharing initiatives with other nations to address these challenges. Evaluating and implementing such measures at the national level will further enhance the quality of medical care in Mongolia.

Inter-laboratory variation for urine albumin among laboratories in a Swedish external quality assessment scheme 2005–2023

IntroductionIncreased albuminuria is associated with elevated mortality. Urine albumin (U-ALB) above 20 mg/L or albumin-to-creatinine ratio (U-ACR) of 3 g/mol are indicative of moderately increased albuminuria. Due to limited standardization among U-ALB methods, diagnosis of increased albuminuria might prove difficult. Materials and methodsData from Equalis’s external quality assessment scheme for low U-ALB levels during 2005–2023 were categorized according to manufacturer and divided into central laboratory (CLAB) and point-of-care testing (POCT) methods. Manufacturer median values were compared to total group mean consensus values and manufacturer CV% was compared at different U-ALB levels. ResultsCLAB was generally closer to consensus values and had lower CV% than POCT at U-ALB levels around 20 mg/L. For CLAB, Roche methods were approximately equal to consensus U-ALB, Abbott 4 % above, and Siemens 5 % below. For POCT, HemoCue was 1 % below, Siemens 7 % above, and Abbott 8 % below. For U-Creatinine, all manufacturers generally had a good agreement differing on average by 1–4 % from consensus. ConclusionsAlthough U-ALB methods generally meet The National Kidney Disease Education Program (NKDEP) recommendations of method bias less than 13 % and imprecision less than 30 %, differences among manufacturers have increased over the last years, with 2023 showing the largest differences between methods. This highlights the need for guidelines for albuminuria and ACR to take method differences into consideration, but also for implementation of suitable urine reference materials.

Evaluation of the External Quality Assessment Scheme as a Performance Tool in Clinical Biochemistry Laboratory in Tertiary Care Centre

Evaluation of the External Quality Assessment Scheme as a Performance Tool in Clinical Biochemistry Laboratory in Tertiary Care Centre

Beyond the basics: Sigma scores in laboratory medicine with variable total allowable errors (TEa)

BackgroundTo diagnose diseases, track the effectiveness of treatments and make well-informed clinical decisions, doctors rely on results from laboratories. Accurate and precise results minimize the necessity for additional testing, saving time and money while enhancing patient satisfaction.. Internal quality control and an external quality assurance scheme(EQAS) are metrics used to evaluate a clinical laboratory’s performance. One of the numerous quality indicators that can be used to gauge the amount of errors is sigma metrics. To calculate the sigma scores bias%, CV%, and Total Error Allowable (TEa) are needed. Total Error allowable(TEa) is a crucial benchmark that establishes allowed limits on the degree of deviation from the target value for a certain analyte. Nevertheless, a proper consensus for establishing a TEa goal has not been reached and the impact of this limiting factor in standard laboratory practice and sigma calculation has not been sufficiently established. Choosing the right Total Error allowable(TEa) goal is one of the greatest challenges when employing sigma metrics as depending on the source, several measurands of TEa values may exhibit alteration. Material and methodsOur study aims to determine the sigma scores of 20 routine chemistry parameters using six different TEa sources: Clinical Laboratory Improvement Amendment (CLIA 88′), CLIA(Clinical Laboratory Improvement Amendment) 24, BDV (Biological Variation Desirable), RCPA(Royal College of Pathologists of Australasia), RiliBak(Guideline of the German Medical Association for Quality Assurance of Laboratory Medical Examinations), and EMC/Spain(Measurement and Control Scheme) over a 12-month period using the bias percent from the External Quality Assessment Scheme (EQAS) and coefficient of variation (CV) from the Internal Quality Control (IQC). Detection system was automated, multi-channel, selective analyzer, the Beckman Coulter AU680 which works on the principle of spectrophotometry. To compute the Sigma metrics, formula used was Sigma = (TEa – Bias%) / CV%. By comparing the sigma values from the different TEa sources, TEa variance on the evaluation of the sigma metric was ascertained after which an internal quality control plan and QGI(Quality Goal Index) for underperforming parameters were devised. ResultsThe study discovered that the sigma values of common chemical parameters varied significantly based on the TEa sources used. Maximum parameters in the above three-sigma zone were TBil, HDL, CK, ALP, amylase and uric acid in CLIA’88 while RCPA and Biological variation were determined to be the most severe, with the highest performing parameters falling below three sigma zones. Rilibaek was the most liberal, with only sodium in the lower three sigma zones along with CLIA’88. The findings indicate that there is the substantial influence of various Total Error Allowable (TEa) sources on the sigma metric evaluation. A quality control plan was devised depending on different sigma scores of the analytes using biorad unity 2.0 software(westgard sigma multirules). The origins of errors that resulted in low sigma ratings liked enhanced cleaning of electrodes, electrode replacement, ageing of reagents, instrument maintainence were pinpointed and addressed. ConclusionThe study highlights the necessity of harmonizing and standardizing sigma metrics, stressing the significance of choosing suitable total error allowable goals (TEa). The creation of worldwide standards and recommendations for total error allowable (TEa) can lead to its harmonization. Establishing a consensus on the acceptable levels of error for various laboratory tests would necessitate the cooperation of specialists from many nations and organizations in order to set such guidelines and standards.

Coagulation factors VIII and factors IX testing practices in China: Results of the 5-year external quality assessment program

Background and aimsTesting for coagulation factors VIII (FVIII) and IX (FIX) plays significant importance in the diagnostic and treatment of hemophilia A and B. External quality assessment (EQA) scheme aimed to assess the participants’ performance of testing for coagulation factors and identify shortcomings in clinical practice. This study aimed to investigate the performance trends of the participating laboratories in China national external quality assessment Scheme (China NEQAS) for FVIII and FIX over a five-year period (2019–2023). Materials and methodsA total of ten external quality assessment (EQA) rounds were conducted from 2019 to 2023 in the China NEQAS for FVIII and FIX. The distribution of method, reagent and instrument were calculated. The trends of method- specific inter-laboratory coefficient of variation (CV) and pass rates were analyzed over 5 years. The dilutions for coagulation factor testing were also investigated. ResultsAll laboratories use one-stage assays to detect FVIII and FIX activity. The inter-laboratory overall CV decreased year by year (10.9 % to 9.3 % for FVIII and 13.5 % to 10.2 % for FIX), and the laboratory pass rate steadily increased (88.0 % to 93.4 % for FVIII and 81.3 % to 92.7 % for FIX). The majority of laboratories employed a single dilution methodology for the assessment of FVIII and FIX activity. The interlaboratory CV was elevated for the Siemens reagent (Actin FSL) during analysis of moderately abnormal FIX concentrations of EQA samples in most batches. ConclusionsThe implementation of the external quality assessment has contributed to facilitate the enhancement of testing quality. Chromogenic assay is a supplement to accurate determination when necessary. Laboratories may choose to perform dilution tests or direct assays to identify the presence of inhibitors, particularly when they are suspected.

High success rate of first proficiency testing for RET fusions and RET mutations in lung and thyroid cancer samples by various methods.

This study describes the external quality assessment (EQA) scheme for molecular testing of RET alterations in non-small cell lung cancer (NSCLC), medullary thyroid carcinomas (MTC), and non-MTC. The lead panel institute and Quality Assurance Initiative in Pathology (Qualitätssicherungs-Initiative Pathologie [QuIP] GmbH) selected formalin-fixed paraffin-embedded (FFPE) tissue from MTC for RET mutation testing by next-generation sequencing (NGS) methods and FFPE tissue from NSCLC and non-MTC for RET gene fusion testing using either in situ hybridisation (ISH) or NGS methods, forming 3 sub-schemes of the EQA scheme. Tissue material underwent an internal validation phase followed by an external testing phase. The internal validation phase served as a cross-validation step conducted by panel institutes. In the external testing phase, the number of participating institutes in the RET point mutation sub-scheme, RET fusion (ISH) sub-scheme, and RET fusion (NGS) sub-scheme was 32, 24, and 38, respectively. The reported success rates for external testing were 96.0%, 89.5%, and 93.5% for the RET point mutation, the ISH RET fusion, and the NGS RET fusion EQA sub-schemes, respectively. These findings confirm the reliability of the NGS method in detecting RET alterations and align with current screening recommendations. Overall, 31 institutes were certified for RET point mutation testing by NGS methods, 22 institutes were certified for RET fusion testing by ISH, and 36 institutes were certified for RET fusion testing by NGS methods. Results can be employed to inform real-world diagnostic decisions in Germany, Austria, and Switzerland.

Detection of soil-transmitted helminths and Schistosoma spp. by nucleic acid amplification test: Results of the first 5 years of the only international external quality assessment scheme.

Infections with soil-transmitted helminths (STH) and schistosomiasis (SCH) result in a significant global health burden, particularly in rural communities in low and middle-income countries. While microscopy remains the primary diagnostic method for STH and SCH in resource-limited settings, nucleic acid amplification tests (NAATs) are gaining prominence as tools for evaluation of public health control programs in endemic countries, and individual diagnosis in high-income countries. Despite the high sensitivity and specificity of NAATs, previous research has highlighted inter-laboratory variations, both in technical and clinical performance, justifying the need for continuous proficiency testing. Results from 5 rounds over a 5-year period of the so far only longitudinal international Helminth External Molecular Quality Assessment Scheme (HEMQAS), coordinated by the Dutch Foundation for Quality Assessment in Medical Laboratories (SKML), were examined in order to (i) assess the diagnostic proficiency of laboratories in detecting helminths in stool and (ii) identify potential factors contributing to variations in performance. Thirty-six laboratories, from 18 countries and 5 continents, participated in HEMQAS. The overall diagnostic performances were satisfying, with remarkably low numbers (<2%) of false-positive results. False-negative results were more often reported for stool (15%) than for DNA (5%) samples. False-negative results varied largely between targets (the highest number (29%) for Trichuris trichiura). Twenty-five laboratories provided a sufficient number of results for a robust comparison between participating laboratories, which confirmed substantial inter-laboratory variability in quantitative NAAT results (Cq-values). This variability likely arises from differences in pre-treatment, DNA isolation and DNA-target amplification procedures. This study emphasizes the complexity of molecular diagnosis for STH and SCH, highlighting the critical role of proper stool preparation and DNA isolation methods. The results underscore the necessity for laboratory professionals and public health decision-makers to recognize these complexities and continuously undertake external quality assessment schemes to ensure accurate and reliable performance in molecular diagnosis.

Implementation of long-read sequencing for routine molecular diagnosis of familial mediterranean fever

BackgroundLong-read sequencing technology, widely used in research, is proving useful in clinical diagnosis, especially for infectious diseases. Despite recent advances, it hasn't been routinely applied to constitutional human diseases. Long-read sequencing detects intronic variants and phases variants, crucial for identifying recessive diseases. MethodsWe integrated long-read sequencing into the clinical diagnostic workflow for the MEFV gene, responsible for familial Mediterranean fever (FMF), using a Nanopore-based workflow. This involved long-range PCR amplification, native barcoding kit library preparation, GridION sequencing, and in-house bioinformatics. We compared this new workflow against our validated method using 39 patient samples and 3 samples from an external quality assessment scheme to ensure compliance with ISO15189 standards. ResultsOur evaluation demonstrated excellent performance, meeting ISO15189 requirements for reproducibility, repeatability, sensitivity, and specificity. Since October 2022, 150 patient samples were successfully analyzed with no failures. Among these samples, we identified 13 heterozygous carriers of likely pathogenic (LP) or pathogenic (P) variants, 1 patient with a homozygous LP/P variant in MEFV, and 4 patients with compound heterozygous variants. ConclusionThis study represents the first integration of long-read sequencing for FMF clinical diagnosis, achieving 100 % sensitivity and specificity. Our findings highlight its potential to identify pathogenic variants without parental segregation analysis, offering faster, cost-effective, and accurate clinical diagnosis. This successful implementation lays the groundwork for future applications in other constitutional human diseases, advancing precision medicine.

Analytical performance specifications for trace elements in biological fluids derived from six countries federated external quality assessment schemes over 10 years.

This article defines analytical performance specifications (APS) for evaluating laboratory proficiency through an external quality assessment scheme. Standard deviations for proficiency assessment were derived from Thompson's characteristic function applied to robust data calculated from participants' submissions in the Occupational and Environmental Laboratory Medicine (OELM) external quality assurance scheme for trace elements in serum, whole blood and urine. Characteristic function was based on two parameters: (1) β- the average coefficient of variation (CV) at high sample concentrations; (2) α- the average standard deviation (SD) at low sample concentrations. APSs weredefined as 1.65 standard deviations calculated by Thompson's approach. Comparison between OELM robust data and characteristic function were used to validate the model. Application of the characteristic function allowed calculated APS for 18 elements across three matrices. Some limitations were noted, particularly for elements (1) with no sample concentrations near analytical technique limit of detection; (2) exhibiting high robust CV at high concentration; (3) exhibiting high analytical variability such as whole blood Tl and urine Pb; (4) with an unbalanced number of robust SD above and under the characteristic function such as whole blood Mn and serum Al and Zn. The characteristic function was a useful means of deriving APS for trace elements in biological fluids where biological variation data or outcome studies were not available. However, OELM external quality assurance scheme data suggests that the characteristic functions are not appropriate for all elements.

The performance of quantitative D-dimer assays in Chinese clinical laboratories by analyzing data from National External quality Assessment Scheme

Background and aimsTo investigate performance of D-dimer assays in China and address analytical quality issues. Materials and methodsD-dimer assays data were collected from China National External Quality Assessment Scheme (China NEQAS) from 2014 to 2022. We analyzed reagents, assay results, reporting unit and cutoffs in 2022 China NEQAS. Interlaboratory coefficient variations (CVs) and influence of modified/unmodified test systems on CVs were investigated over 9 years. ResultsThere were 82 reagent brands in China NEQAS, but 55 reagent instructions did not indicate expression unit (DDU or FEU). Up to 7-fold of the ratio of max-to-min mean results was shown among different assays with same unit on the same sample. A prevalence of FEU (63.4%) over DDU (17.1%) was observed. Although 669 laboratories (37.9%) among 1766 laboratories used reagents without VTE exclusion claim, they also reported cutoffs. The CVs of only two assays were decreasing over years. CVs of modified test systems were higher than those of unmodified systems before improvement. ConclusionsExpression unit should be required to label in package inserts by regulatory authority. Laboratory professionals should follow instructions for use and prefer unmodified test systems for clinical safely application. Harmonization of reporting units through collaborative efforts is the promising step.

External Quality Assessment (EQA) scheme for serological diagnostic test for SARS-CoV-2 detection in Sicily Region (Italy), in the period 2020-2022.

Since December 2019, worldwide public health has been exposed to a severe acute respiratory syndrome caused by Coronavirus-2. Serological testing is necessary for retrospective assessment of seroprevalence rates, and the determination of vaccine response and duration of immunity. For this reason, it was necessary to introduce a panel of tests able to identify and quantify Covid-19 antibodies. As a Regional Reference Centre, the CRQ Laboratory (Regional Laboratory for the Quality Control) developed and conducted an External Quality Assessment (EQA) panel of assays, to evaluate the quality of various methods, that were used by 288 Sicilian laboratories, previously authorized on behalf of the Public Health Service. The performance test was based on pooled samples with different levels of concentration of antibodies. 97 , 98, and 95 % of the participating laboratories tested all samples correctly in 2020, 2021, and 2022 respectively. The best performance was observed in the test of total Ig. The general performance of laboratories improved over the years. The incorrect diagnosis had and could still have important implications on vaccination cycles. Only through the effort of laboratory professionals, and the extension of the EQA scheme, a better harmonization of methods, protocols, and thus results, to guarantee a better healthcare system, will be possible.

A Collaborative Self-supervised Domain Adaptation for Low-Quality Medical Image Enhancement.

Medical image analysis techniques have been employed in diagnosing and screening clinical diseases. However, both poor medical image quality and illumination style inconsistency increase uncertainty in clinical decision-making, potentially resulting in clinician misdiagnosis. The majority of current image enhancement methods primarily concentrate on enhancing medical image quality by leveraging high-quality reference images, which are challenging to collect in clinical applications. In this study, we address image quality enhancement within a fully self-supervised learning setting, wherein neither high-quality images nor paired images are required. To achieve this goal, we investigate the potential of self-supervised learning combined with domain adaptation to enhance the quality of medical images without the guidance of high-quality medical images. We design a Domain Adaptation Self-supervised Quality Enhancement framework, called DASQE. More specifically, we establish multiple domains at the patch level through a designed rule-based quality assessment scheme and style clustering. To achieve image quality enhancement and maintain style consistency, we formulate the image quality enhancement as a collaborative self-supervised domain adaptation task for disentangling the low-quality factors, medical image content, and illumination style characteristics by exploring intrinsic supervision in the low-quality medical images. Finally, we perform extensive experiments on six benchmark datasets of medical images, and the experimental results demonstrate that DASQE attains state-of-the-art performance. Furthermore, we explore the impact of the proposed method on various clinical tasks, such as retinal fundus vessel/lesion segmentation, nerve fiber segmentation, polyp segmentation, skin lesion segmentation, and disease classification. The results demonstrate that DASQE is advantageous for diverse downstream image analysis tasks.

Method optimization for a simultaneous determination of neonicotinoid, carbamate/thiocarbamate, triazole, organophosphate and pyrethroid pesticides and their metabolites in urine using UPLC-MS/MS

An accurate and sensitive method for the determination of a total of 23 pesticides and their metabolites in human urine has been optimised. The methodology is based on a previously published method based on solid-phase extraction with methanol and acetone followed by ultra-performance liquid chromatography coupled to tandem mass spectrometry (UPLC-MS/MS) in the selected reaction mode (SRM) with both positive and negative electrospray ionization (ESI+/-). The detection settings of the previous method, which allowed to determine the metabolites from 6 organophosphate and 2 pyrethroid pesticides, were optimised in order to include further pesticide groups, such as 11 neonicotinoids, 3 carbamates/thiocarbamates and 2 triazoles. The 5-windows method enduring 22 min was optimized with acceptable results in relation to accuracy (recoveries >75 %), precision (coefficients of variation <26 %) and linearity (R2> 0.9915). The limits of detection ranged between 0.012 ng/mL and 0.058 ng/mL. Samples from the German External Quality Assessment Scheme (G-EQUAS) encompassing 2 pyrethroids, 2 organophosphate and one neonicotinoid (6-chloronicotinic acid, a common metabolite of imidacloprid and acetamiprid) were analysed, and the latter, included in this newest optimization, provided good reference results. The method is optimal as a human biomonitoring tool for health risk assessment in large population surveys.

NEED OF EXTERNAL QUALITY ASSESSMENT SCHEME – AN EXPERIENCE IN CENTRAL LABORATORY AT RNTMC, UDAIPUR

Objectives: The objectives of the study are to periodically assess the quality of the external quality assessment scheme (EQAS) with the aim of enhancing laboratory performances. Methods: An observational study was done at our central laboratory at RNTMC, Udaipur, after approval from the institutional review board. Our laboratory receives quarterly blood samples and already prepared slides from AIIMS, Delhi, for complete blood count (CBC). In addition, lyophilized blood samples for fibrinogen, prothrombin time/international normalized ratio (PT/INR), and activated partial thromboplastin time (APTT) analysis are received quarterly from CMC, Vellore, through courier package. As for cytopathology, the third package includes already prepared 10 slides of 2 cycles for cytopathology analysis along with a brief clinical history. Results: CBC, peripheral blood film examination findings, and reticulocyte count results were consistently acceptable, except in August 2021, December 2022, and March 2023 when some parameters of CBC were deemed unacceptable. Results for PT/INR, APTT, and fibrinogen were within consensus at all-time except in March 2022, when they were out within consensus and deemed unacceptable. Similarly, results for cytopathology evaluation were in concordance with the results of the provider except for a few occasions were deviations were seen for some diagnoses due to interpretation error. Conclusion: Engaging in EQAS has facilitated the enhancement of test result accuracy, thereby improving the overall quality of laboratory practices and minimizing erroneous outcomes.

Quality assurance for next-generation sequencing diagnostics of rare neurological diseases in the European Reference Network.

In the past decade, next-generation sequencing (NGS) has revolutionised genetic diagnostics for rare neurological disorders (RND). However, the lack of standardised technical, interpretative, and reporting standards poses a challenge for ensuring consistent and high-quality diagnostics globally. To address this, the European Reference Network for Rare Neurological Diseases (ERN-RND) collaborated with the European Molecular Genetics Quality Network (EMQN) to establish an external quality assessment scheme for NGS-based diagnostics in RNDs. The scheme, initiated in 2021 with a pilot involving 29 labs and followed by a second round in 2022 with 42 labs, aimed to evaluate the performance of laboratories in genetic testing for RNDs. Each participating lab analysed genetic data from three hypothetical cases, assessing genotyping, interpretation, and clerical accuracy. Despite a majority of labs using exome or genome sequencing, there was considerable variability in gene content, sequencing quality, adherence to standards, and clinical guidance provision. Results showed that while most labs provided correct molecular diagnoses, there was significant variability in reporting technical quality, adherence to interpretation standards, reporting strategies, and clinical commentary. Notably, some labs returned results with the potential for adverse medical outcomes. This underscores the need for further harmonisation, guideline development, and external quality assessment in the evolving landscape of genomic diagnostics for RNDs. Overall, the experience with the scheme highlighted the generally good quality of participating labs but emphasised the imperative for ongoing improvement in data analysis, interpretation, and reporting to enhance patient safety.

Diagnostic performance of mpox virus (MPXV) real-time PCR assays: multicenter assessment and extended sensitivity analysis.

To comprehensively investigate the diagnostic performance of routinely used assays in MPXV testing, the National Center of Clinical Laboratories in China conducted a nationwide external quality assessment (EQA) scheme and an evaluated nine assays used by ≥ 5 laboratories in the EQA. MPXV virus-like particles with 2700, 900 and 300 copies/mL were distributed to 195 EQA laboratories. For extended analysis, triple-diluted samples from 9000 to 4.12 copies/mL were repeated 20 times using the assays employed by ≥ 5 laboratories. The diagnostic performance was assessed by analyzing EQA data and calculating the limits of detection (LODs). The performance was competent in 87.69% (171/195) of the participants and 87.94% (175/199) of the datasets. The positive percentage agreements (PPAs) were greater than 99% for samples at 2700 and 900 copies/mL, and 95.60% (761/796) for samples at 300 copies/mL. The calculated LODs for the two clades ranged from 228.44 to 924.31 copies/mL and were greater than the LODs specified by the respective kits. EasyDiagnosis had the lowest calculated LODs and showed superior performance in EQA, whereas BioGerm and Sansure, with higher calculated LODs, did not perform well in EQA. This study provides valuable information from the EQA data and evaluation of the diagnostic performance of MPXV detection assays. It also provided insights into reagent optimization and enabled prompt public health interventions for the outbreak.

External quality assessment schemes in bacteriology support public health in Germany-results from 2006 to 2023.

External Quality Assessment schemes (EQAS) are mandatory to ensure quality standards in diagnostic methods and achieve laboratory accreditation. As host institution for two German culture-based bacteriology EQAS (RV-A and RV-B), we investigated the obtained data of 590 up to 720 surveys per year in RV-A and 2,151 up to 2,929 in RV-B from 2006 to 2023. As educational instruments, they function to review applied methodology and are valuable to check for systemic- or method-dependent failures in microbiology diagnostics or guidelines. Especially, containment of multi-resistant bacteria in times of rising antibiotic resistance is one major point to assure public health. The correct identification and reporting of these strains is therefore of high importance to achieve this goal. Moreover, correct antimicrobial susceptibility testing (AST) per se is important for selecting appropriate therapy, to restrict broad-spectrum antibiotics and minimize resistance development. The reports of participating laboratories displayed a high level of correct identification results in both schemes with mostly consistent failure rates around 2.2% (RV-A) and 3.9% (RV-B) on average. In contrast, results in AST revealed increasing failure rates upon modification of AST requirements concerning adherence to standards and subsequent bacterial species-specific evaluation. Stratification on these periods revealed in RV-A a moderate increase from 1.3% to 4.5%, while in RV-B failure rates reached 14% coming from 4.3% on average. Although not mandatory, subsequent AST evaluation and consistent reporting are areas of improvement to benefit public health.