Interlaboratory Proficiency Testing Research Articles

Participating in VER-IPT: is it worth the effort?

Interlaboratory proficiency tests (IPTs) are an essential tool to maintain quality standards and performances of diagnostic laboratories at a high level. In 2022 the VER IPT reached its 4th edition. The panel consisted of 10 ampoules that contained all known genotypes of Betanodavirus, the causative agent of Viral Encephalopathy and Retinopathy. Detecting the presence or absence of the target in the samples by real time or conventional RT-PCR was the main target of the IPT. Species identification to be performed by sequencing or by any other method available at the participant’s laboratory was also encouraged. Twenty-four laboratories out of 25 participants completed the exercise on time. Thirteen out of 24 (54.16% of participants) obtained the maximum score, while the remaining 11 produced a percentage of correct results ranging between 70%-90%, achieving an overall good outcome. Notably, in this IPT edition the BFNNV (barfin flounder nervous necrosis virus) was included for the first time and did not pose any particular problems in its detection. Viral species identification gave results far below the expectations and only 50% of the participants completed this part of the exercise, scoring quite well; however, laboratories should make greater efforts in improving their capacity to correctly identify the genotype.

Quartet metabolite reference materials for inter-laboratory proficiency test and data integration of metabolomics profiling

BackgroundVarious laboratory-developed metabolomic methods lead to big challenges in inter-laboratory comparability and effective integration of diverse datasets.ResultsAs part of the Quartet Project, we establish a publicly available suite of four metabolite reference materials derived from B lymphoblastoid cell lines from a family of parents and monozygotic twin daughters. We generate comprehensive LC–MS-based metabolomic data from the Quartet reference materials using targeted and untargeted strategies in different laboratories. The Quartet multi-sample-based signal-to-noise ratio enables objective assessment of the reliability of intra-batch and cross-batch metabolomics profiling in detecting intrinsic biological differences among the four groups of samples. Significant variations in the reliability of the metabolomics profiling are identified across laboratories. Importantly, ratio-based metabolomics profiling, by scaling the absolute values of a study sample relative to those of a common reference sample, enables cross-laboratory quantitative data integration. Thus, we construct the ratio-based high-confidence reference datasets between two reference samples, providing “ground truth” for inter-laboratory accuracy assessment, which enables objective evaluation of quantitative metabolomics profiling using various instruments and protocols.ConclusionsOur study provides the community with rich resources and best practices for inter-laboratory proficiency tests and data integration, ensuring reliability of large-scale and longitudinal metabolomic studies.

European Inter-Laboratory Proficiency Test for Dourine Antibody Detection Using the Complement Fixation Test.

Dourine is a sexually transmitted parasitic disease affecting equids. Its causative agent is referred to as Trypanosoma equiperdum and the prescribed serodiagnosis method is the complement fixation test (CFT). In the context of our European Reference Laboratory mandate for equine diseases (excluding African horse sickness), we organised dourine CFT inter-laboratory proficiency tests (ILPTs) in 2015, 2018 and 2022 to evaluate the performance of the European Union network of National Reference Laboratories (NRLs) for dourine. ILPT panels were composed of horse sera with or without antibodies against Trypanosoma spp. originating from non-infected, immunised or experimentally infected horses. Twenty-two NRLs participated in at least one of the three sessions. In 2015, 2018 and 2022, the percentage of laboratories obtaining 100% of the expected results was 57, 90 and 80, respectively. These dourine CFT ILPTs showed the benefits of standardising the method's detection limit and underlined the constant need to evaluate NRLs to improve the network's performance. These results also argue in favour of the need for a representative bio-bank to improve the representativeness of ILPT samples and to allow the adoption of alternative serological methods for international surveillance of dourine.

Results of the 2020 Genomic Proficiency Test for the network of European Union Reference Laboratory for Antimicrobial Resistance assessing whole-genome-sequencing capacities.

The global surveillance and outbreak investigation of antimicrobial resistance (AMR) is amidst a paradigm shift from traditional biology to bioinformatics. This is due to developments in whole-genome-sequencing (WGS) technologies, bioinformatics tools, and reduced costs. The increased use of WGS is accompanied by challenges such as standardization, quality control (QC), and data sharing. Thus, there is global need for inter-laboratory WGS proficiency test (PT) schemes to evaluate laboratories' capacity to produce reliable genomic data. Here, we present the results of the first iteration of the Genomic PT (GPT) organized by the Global Capacity Building Group at the Technical University of Denmark in 2020. Participating laboratories sequenced two isolates and corresponding DNA of Salmonella enterica, Escherichia coli and Campylobacter coli, using WGS methodologies routinely employed at their laboratories. The participants' ability to obtain consistently good-quality WGS data was assessed based on several QC WGS metrics. A total of 21 laboratories from 21 European countries submitted WGS and meta-data. Most delivered high-quality sequence data with only two laboratories identified as overall underperforming. The QC metrics, N50 and number of contigs, were identified as good indicators for high-sequencing quality. We propose QC thresholds for N50 greater than 20 000 and 25 000 for Campylobacter coli and Escherichia coli, respectively, and number of contigs >200 bp greater than 225, 265 and 100 for Salmonella enterica, Escherichia coli and Campylobacter coli, respectively. The GPT2020 results confirm the importance of systematic QC procedures, ensuring the submission of reliable WGS data for surveillance and outbreak investigation to meet the requirements of the paradigm shift in methodology.

Analysis of Clinical Laboratory Detecting Challenging Variants from Exome Sequencing Using Simulated Patient–Parent Trio Sample: Pilot Study for Neurodevelopmental Disorder de Novo Variants

To date, there has been no systematic analysis for the clinical laboratory in detecting technically challenging variants using the trio-based exome sequencing (ES) approach. Here, we present an interlaboratory pilot proficiency testing study that used synthetic patient-parent specimens to assess the detection of challenging variants with de novo dominant inheritance modes for neurodevelopmental disorders using various trio-based ES. In total, 27 clinical laboratories that performed diagnostic exome analyses participated in the survey. One of the 26 challenging variants was identified by all laboratories, whereas all 26 variants were identified by only nine laboratories. The lack of identification of mosaic variants was often due to the bioinformatics analysis that excluded the variant. For missing intended heterozygous variants, probable root causes were related to the technical bioinformatics pipeline and variant interpretation and reporting. For each missing variant, there may be more than one probable reason from the different laboratories. There was considerable variation in interlaboratory performance for detecting challenging variants using trio-based ES. This finding may have important implications for the design and validation of tests for different variant types in clinical laboratories, especially for technically challenging variants, and necessary workflow modification can potentially improve trio-based ES performance.

Busulfan Interlaboratory Proficiency Testing Program Revealed Worldwide Errors in Drug Quantitation and Dose Recommendations.

The clinical outcomes of busulfan-based conditioning regimens for hematopoietic cell transplantation (HCT) have been improved by personalizing the doses to target narrow busulfan plasma exposure. An interlaboratory proficiency test program for the quantitation, pharmacokinetic modeling, and busulfan dosing in plasma was developed. Previous proficiency rounds (ie, the first 2) found that 67%-85% and 71%-88% of the dose recommendations were inaccurate, respectively. A proficiency test scheme was developed by the Dutch Foundation for Quality Assessment in Medical Laboratories (SKML) and consisted of 2 rounds per year, with each round containing 2 busulfan samples. In this study, 5 subsequent proficiency tests were evaluated. In each round, the participating laboratories reported their results for 2 proficiency samples (ie, low and high busulfan concentrations) and a theoretical case assessing their pharmacokinetic modeling and dose recommendations. Descriptive statistics were performed, with ±15% for busulfan concentrations and ±10% for busulfan plasma exposure. The dose recommendations were deemed accurate. Since January 2020, 41 laboratories have participated in at least 1 round of this proficiency test. Over the 5 rounds, an average of 78% of the busulfan concentrations were accurate. Area under the concentration-time curve calculations were accurate in 75%-80% of the cases, whereas only 60%-69% of the dose recommendations were accurate. Compared with the first 2 proficiency test rounds (PMID 33675302, October, 2021), the busulfan quantitation results were similar, but the dose recommendations worsened. Some laboratories repeatedly submit results that deviated by more than 15% from the reference values. The proficiency test showed persistent inaccuracies in busulfan quantitation, pharmacokinetic modeling, and dose recommendations. Additional educational efforts have yet to be implemented; regulatory efforts seem to be needed. The use of specialized busulfan pharmacokinetic laboratories or a sufficient performance in busulfan proficiency tests should be required for HCT centers that prescribe busulfan.

Non-targeted authentication of black pepper using a local web platform: Development, validation and post-analytical challenges of a combined NIR spectroscopy and LASSO method

Black pepper is a valuable commodity susceptible to economically motivated adulterations. This contribution describes the proper development, standardization, validation and late-stage validation of a non-targeted method for authentication of black pepper by near-infrared spectroscopy (NIR) coupled to a least absolute shrinkage and selection operator (LASSO). Note that this is the first successful attempt to apply the LASSO method to infrared spectroscopy data. We analysed 150 diverse samples of black pepper supplied by a well-recognized spice trader. A first batch of samples (n = 116) were split into training and test sets and then normalized by multiplicative scatter correction (MSC). While the test set was withheld for further testing of the model, the training set was submitted to the LASSO method with the aim of retrieving the discriminant spectral features and classifying the samples as authentic, exogenously-adulterated or endogenously-adulterated. The model was tested on the test set, achieving an overall accuracy of 94% with very high sensitivity and specificity rates. Furthermore, an R-based local web platform was created for immediate prediction of the samples from raw data. The NIR user simply uploads the raw data to the local web application and MSC normalization on the stored training set and interrogation of the LASSO classifier are performed. The online application facilitates the model testing and enables clear visualization of the outcomes. After the creation of the local web platform, the classifier was then validated with a new batch of independent samples, resulting in the correct prediction of 33/34 samples. The robustness of this non-targeted method and its stability over time was further established, and a late-stage validation of the classifier was successfully performed by an inexperienced user. Finally, the LASSO classifier was successfully challenged with a sample from an international inter-laboratory proficiency test. • A non-targeted method for authentication of black pepper by NIR & LASSO. • A web application was created for direct classification of NIR raw data. • Validation and late-stage challenges of the method were carried out. • Successful participation to an international proficiency test.

Quantification of phosphatidylethanol combining dried blood spots sampling with Orbitrap-based LC-HRMS platform: Method validation and proficiency testing

Phosphatidylethanols (PEth) are phospholipids specifically synthetised by an enzymatic reaction in presence of ethanol. PEth is a mid-term direct biomarker for alcohol consumption or abstinence, leading to a growing interest for forensic toxicology purposes. Blood deposition onto a filter paper card as dried blood spots (DBS) allows PEth stabilisation which is otherwise easily degraded at room temperature. The goal of this study was to develop and validate a procedure for the quantification of PEth 16:0/18:1, the most abundant analogue, in DBS samples benefiting from the selectivity brought by Orbitrap-based high-resolution mass spectrometry (HRMS). Calibration samples and quality controls (QCs) are volumetrically spotted (10 μL) onto filter paper card (Whatman 903 protein saver) either using HemaXis DB10™ device, or using laboratory micropipette. The whole DBS is manually punched out and the PEth is then directly extracted using an in vial approach with 100 μL of PEth 16:0/18:1-D5 in methanol. Analyses are then performed by LC-HRMS in PRM mode using a QExactive Orbitrap platform. Validation was carried out on with respect to the Food and Drug Administration (FDA) criteria, using three different QC concentrations (39, 87 and 350 ng/mL) over three non-consecutive days. To assess the robustness of our method, an interlaboratory proficiency testing was carried out using 3 different commercial standards at 4 levels (50, 100, 200, and 300 ng/mL) of quality controls (QCs) provided by ACQ Science (Germany). The method was fully validated according to guidelines set forth by the FDA. Calibration curve was built using a weighting factor of 1/x. Trueness was measured between 100.1 and 103.6% for the tested concentrations. Repeatability and intermediate precision were found to be lower than 5%. Linearity was evaluated between the lower limit of quantification of 20 ng/mL and the upper limit of quantification of 2000 ng/mL with an R2 greater than 0.998. Recovery (RE) and matrix effect (ME) evaluated at 2 concentrations ranged from 76 to 99% and 8 to 10%, respectively. During the proficiency test, precision was evaluated below 8.0%, while the accuracy ranged from 93.8% to 105.9% and from 101 to 104.5% when compared with the expected concentration and the mean measured value of all the labs participating respectively. The validation results demonstrate that the use of Orbitrap-based PRM quantification present an interesting alternative over triple quadrupole platforms considered as the gold standard for LC-MS/MS quantitative approaches. Indeed, multiple reaction monitoring (MRM) and PRM provide comparable performance in terms of sensitivity, linearity, dynamic range, precision and repeatability. Moreover, the use of PRM provides access to the full fragmentation spectra without any preanalytical considerations. The proficiency testing results confirm the suitability of PRM mode showing great quantification performances. In addition, those results and especially the repeatability exhibit the precision of the volume control provided by the use of HemaXis™ device. This tool enables the standardisation of the DBS collection at the fingertip in a non-hospital environment either by minimally-trained medical staff or by the patient himself. A rapid, sensitive, and robust method was developed and fully validated for the detection and quantification of PEth 16:0/18:1 in DBS samples. The results of the validation process and the proficiency testing confirm that the use of DBS associated with HRMS PRM-based analyses does not hinder the analytical performances, while providing full information over the MS-MS spectra. The development of analytical tools enabling the use of DBS microsampling that can be performed in almost every environment opens new opportunities toward clinical and forensic toxicological applications.

Evaluation of Pre-Analytical and Analytical Methods for Detecting SARS-CoV-2 in Municipal Wastewater Samples in Northern Italy

(1) Background: The surveillance of SARS-CoV-2 RNA in urban wastewaters allows one to monitor the presence of the virus in a population, including asymptomatic and symptomatic individuals, capturing the real circulation of this pathogen. The aim of this study was to evaluate the performance of different pre-analytical and analytical methods for identifying the presence of SARS-CoV-2 in untreated municipal wastewaters samples by conducting an inter-laboratory proficiency test. (2) Methods: three methods of concentration, namely, (A) Dextran and PEG-6000 two-phase separation, (B) PEG-8000 precipitation without a chloroform purification step and (C) PEG-8000 precipitation with a chloroform purification step were combined with three different protocols of RNA extraction by using commercial kits and were tested by using two primers/probe sets in three different master mixes. (3) Results: PEG-8000 precipitation without chloroform treatment showed the best performance in the SARS-CoV-2 recovery; no major differences were observed among the protocol of RNA extraction and the one-step real-time RT-PCR master mix kits. The highest analytic sensitivity was observed by using primers/probe sets targeting the N1/N3 fragments of SARS-CoV-2. (4) Conclusions: PEG-8000 precipitation in combination with real-time RT-PCR targeting the N gene (two fragments) was the best performing workflow for the detection of SARS-CoV-2 RNA in municipal wastewaters.

Development of Avocado Reference Material for Pesticide Residue Analysis.

Pesticide quantitation in foods relies on the availability of matrix reference materials, which, however, are scarce because of the general instability of pesticides. In particular, no avocado reference material has been developed. This research aimed to develop a reference material to support the determination of pesticide residues in avocado. Avocado was spiked with 11 selected pesticides at levels of 0.01-0.35 mg/kg. The production process included the assessment of between-unit heterogeneity, stability during dispatch, and best storage conditions according to ISO 17034. Reference values were estimated through an interlaboratory comparison study involving laboratories of demonstrated competence and adhering to ISO/IEC 17025. The corresponding expanded uncertainties were calculated as 4-19% in compliance with the Guide to the Expression of Uncertainty in Measurement. The reference material was sufficiently homogeneous and stable at 4°C during the entire study period (365 days) for most of the pesticides, and at 40°C during 10 days, but it was unstable at 50 and 60°C during 10 days. Four pesticides showed downward trends; however, this behavior was considered in the uncertainty budget. As this material complied with all requirements of proficiency testing, it was used in an interlaboratory proficiency test designed to investigate analytical performance and assist laboratories in improving the quality of measurement results. The presented material can be used for the development of novel analytical methods or in-house reference materials and adds to the scarce supply of reference materials for the determination of pesticides in vegetable matrixes with high oil contents and intermediate water contents. A novel reference material has been developed for the reliable and accurate quantitation of multiple pesticides in avocado, allowing researchers to avoid the preparation of in-house reference materials for this purpose.

Determination of glucosamine in functional food samples by high performance liquid chromatography (HPLC-FLD)

A simple, rapid and specific method using high performance liquid chromatography with fluorescence detector (HPLC-FLD) was developed for quantification of glucosamine in supplements after derivatization with 9-fluorenylmethyl chloroformate (FMOC-Cl). The chromatographic separation was achieved on a C18 column (150 mm × 4.6 mm × 5 µm) using a gradient mobile phase containing acetonitrile and water at a flow rate of 1.0 mL/min. The FLD detector was operated at excitation and emission wavelengths of 265 and 315 nm, respectively. The analytical method was validated for specificity, linearity, accuracy, and precision. The detector response for glucosamine was linear over the selected concentration range from 6.7 to 135 ppm with a correlation coefficient of 0.9988. The repeatability (RSD, n = 6) and reproducibility (RSD, n = 4) were from 2.54 to 3.23 % and from 2.24 to 3.07 %, respectively. The recovery was between 98.0 and 101.5 %. In addition, we also joined the interlaboratory proficiency testing program (code: H21.11) organized by the National Institute of Food Control with good result (z-score value was - 0.89 < 2). The method was successfully applied for the analysis of glucosamine in 15 supplement samples.

Inter-laboratory Pressure Comparison Measurement In Gas Medium at ± 150 hPa Range

Results of interlaboratory comparisons and proficiency tests are a significant parameter for the calibration and testing laboratories for assuring the quality of test and calibration results performed by those laboratories. Accredited and non-accredited laboratories that have a quality system for their working areas are expected to join into inter-comparisons and proficiency tests in certain periods to show a degree of equivalence among the participant laboratories and assure their service quality. The necessity of participating in comparison measurements (ILC) and proficiency tests (PT) are stated in the EN ISO/IEC 17025:2017 International Standard that accredited laboratories or laboratories applying for accreditation must participate in ILC and PT from parameters related to measurement quantities within the scope of accreditation and have achieved successful results, and it is also a requirement sought by accreditation bodies. This study gives the organisation steps and the obtained results of a bilateral pressure comparison measurement of digital pressure gauge in the hydraulic medium between UME and an accredited laboratory in industry between ± 150 hPa.

Inter-laboratory Comparisons and Their Roles in Accreditation

Results of interlaboratory comparisons and proficiency tests are a significant parameter for the calibration and testing laboratories for assuring the quality of test and calibration results performed by those laboratories. If test and calibration laboratories want to demonstrate that they operate according to a management system, that they are technically competent and that they can produce technically valid results in the tests and calibrations they perform for their customers, the general requirements they must meet are defined in ISO/IEC 17025:2017. This international standard forms the basis of international laboratory accreditation. Clause 7.7 Ensuring the validity of results in this standard requires laboratories to establish the procedures and instructions and other technical documentation needed to ensure the results of the tests and calibrations they perform. Participation in inter-laboratory comparison or proficiency testing programs is one of the most important of these activities. Participation in inter-laboratory comparisons provides an opportunity for laboratories to independently evaluate their analytical performance, both in absolute terms and in comparison, to other techniques. In this study, information about calibration laboratories and accreditation activities is given and the importance of inter-laboratory comparison studies is explained to ensure the results of the measurements made by calibration laboratories.

Разработка централизованного подхода к проведению межлабораторных сличительных испытаний

Важнейшим звеном системы контроля качества нефти являются испытательные лаборатории, от компетентности которых зависит достоверность результатов измерений и эффективность управленческих решений, принимаемых с учетом полученных данных. Одним из способов подтверждения достоверности результатов измерений является проверка квалификации лаборатории посредством ее участия в межлабораторных сличительных (сравнительных) испытаниях (МСИ). В настоящей статье рассмотрены вопросы проведения таких испытаний для лабораторий организаций системы «Транснефть». Описан действующий порядок, предполагающий участие лабораторий в МСИ в регионах своего местонахождения, при этом разработкой и реализацией программы проверки квалификации занимаются сторонние организации - провайдеры МСИ. Такая практика имеет существенные недостатки, не позволяя, в том числе, систематизировать и обобщить результаты МСИ для общей оценки деятельности испытательных лабораторий ПАО «Транснефть». В статье представлен централизованный подход к проведению МСИ в ПАО «Транснефть», устанавливающий единый порядок участия лабораторий в испытаниях с целью осуществления общей оценки квалификации лабораторий, своевременной разработки и реализации предупреждающих и корректирующих мероприятий по улучшению деятельности лабораторий, усовершенствования системы контроля качества нефти на объектах ПАО «Транснефть». The most important link in the oil quality control system are testing laboratories, the competence of which determines the reliability of measurement results and the effectiveness of management decisions based on the data obtained. One way to confirm the validity of measurement results is to verify the laboratory qualifications through its participation in interlaboratory proficiency (comparative) tests (IPT). This article considers the issues of such tests for the laboratories of Transneft system entities. The current procedure is described, which involves the participation of laboratories in the IPT in the regions of their location, while the development and implementation of the proficiency testing program is carried out by third-party IPT provider organizations. This practice has significant drawbacks, not allowing, among other things, to systematize and summarize the results of IPT for an overall assessment of the activities of Transneft PJSC’s testing laboratories. The article presents a centralized approach to conducting IPT in Transneft PJSC, which establishes a unified procedure for the participation of laboratories in tests in order to implement an overall assessment of laboratory qualification, timely development and implementation of preventive and corrective measures to improve the performance of laboratories and improve the oil quality control system at the Transneft PJSC facilities.

A technique for diagnostics of micro-inclusions in the objects of soil and geological origin: validation and practical application

A method for diagnosing microinclusions in the objects of soil and geological origin is developed on the basis of the Atlas of microinclusions in soils (hereinafter referred to as the Atlas). The validation procedure and an example of the practical application of the developed technique are considered. A review of the content and structure of the Atlas, which contains 37 types of microinclusions is presented. Diagnosis of microinclusions is carried out using the Atlas key which is a sequence of identifying diagnostic features (transparency, shape, color, gloss, fracture, structure, as well as density, magnetic properties, hardness, brittleness) for different types of microinclusions. A scheme for determining the nature of a microinclusion (red brick) using the Atlas key is given as an example. The validation procedure of this method consists in experimental verification of the reliability of testing and evaluation of the reproducibility of test results under different conditions: when examining samples of various complexity by several performers at different times using different stereo microscopes. We used 17 soil samples that were previously (2 – 8 years ago) tested and stored as control samples in a laboratory collection of site-collected samples. One part of the samples was examined in usual forensic soil examinations, the other was studied in the framework of participation in the procedure of interlaboratory proficiency testing under the ENFSI (European Network of Forensic Science Institutions). Two experts performed independent studies of control samples at different times. It is shown that the composition of the complex of microinclusions (by type and number) in each of the studied samples coincides with the composition of the corresponding control sample. The experts performed 108 tests, and there were no erroneous results which indicates the reproducibility of the test results and the competence of the experts. An example of the practical application of the developed technique is given.

Interlaboratory proficiency tests for the detection of staphylococcal enterotoxin type A in food.

Staphylococcal enterotoxins (SEs) are among the leading causes of food intoxications, affecting consumer health even in nanogram (ng) amounts. In the European Union, certain food safety criteria are specified, including the absence of SEs in cheeses, milk powder and whey powder. Until 2019, the analytical reference method used was the European Screening Method, which was replaced by EN ISO 19020. For the official laboratories involved in food control, the German Reference Laboratory for coagulase-positive staphylococci including Staphylococcus aureus organized three interlaboratory proficiency tests (ILPTs) to detect SE type A in food during the years 2013-2018. The selected food products (cream cheese and vanilla pudding) were successfully tested beforehand with regard to easy handling, homogeneity and stability of the added toxin. In 2013, ILPT participants overall were not competent in detecting SE type A in food. The following factors were identified to improve the performance: (i) concentration of sample extract using dialysis; (ii) selection of a sensitive detection kit; and (iii) proper sample handling. By taking these factors into account and instructing and training the laboratories, their competence greatly improved. In 2018, all performance criteria (specificity, sensitivity and accuracy) were >90%, even at very low concentrations of SE type A of approximately 0·01ngg-1 food.

External quality assessment of Rift Valley fever diagnosis in countries at risk of the disease: African, Indian Ocean and Middle-East regions.

Rift Valley fever virus (RVFV), an arbovirus belonging to the Phlebovirus genus of the Phenuiviridae family, causes the zoonotic and mosquito-borne RVF. The virus, which primarily affects livestock (ruminants and camels) and humans, is at the origin of recent major outbreaks across the African continent (Mauritania, Libya, Sudan), and in the South-Western Indian Ocean (SWIO) islands (Mayotte). In order to be better prepared for upcoming outbreaks, to predict its introduction in RVFV unscathed countries, and to run efficient surveillance programmes, the priority is harmonising and improving the diagnostic capacity of endemic countries and/or countries considered to be at risk of RVF. A serological inter-laboratory proficiency test (PT) was implemented to assess the capacity of veterinary laboratories to detect antibodies against RVFV. A total of 18 laboratories in 13 countries in the Middle East, North Africa, South Africa, and the Indian Ocean participated in the initiative. Two commercial kits and two in-house serological assays for the detection of RVFV specific IgG antibodies were tested. Sixteen of the 18 participating laboratories (88.9%) used commercial kits, the analytical performance of test sensitivity and specificity based on the seroneutralisation test considered as the reference was 100%. The results obtained by the laboratories which used the in-house assay were correct in only one of the two criteria (either sensitivity or specificity). In conclusion, most of the laboratories performed well in detecting RVFV specific IgG antibodies and can therefore be considered to be prepared. Three laboratories in three countries need to improve their detection capacities. Our study demonstrates the importance of conducting regular proficiency tests to evaluate the level of preparedness of countries and of building a network of competent laboratories in terms of laboratory diagnosis to better face future emerging diseases in emergency conditions.

Viral Encephalo-Retinopathy Interlaboratory Proficiency Test (VER-IPT): results from two years' experience

Viral Encephalo-Retinopathy Interlaboratory Proficiency Test (VER-IPT): results from two years' experience

Quality Control of Busulfan Plasma Quantitation, Modeling, and Dosing: An Interlaboratory Proficiency Testing Program.

Personalizing busulfan doses to target a narrow plasma exposure has improved the efficacy and lowered the toxicity of busulfan-based conditioning regimens used in hematopoietic cell transplant. Regional regulations guide interlaboratory proficiency testing for busulfan concentration quantification and monitoring. To date, there have been no comparisons of the busulfan pharmacokinetic modeling and dose recommendation protocols used in these laboratories. Here, in collaboration with the Dutch Association for Quality Assessment in Therapeutic Drug Monitoring and Clinical Toxicology, a novel interlaboratory proficiency program for the quantitation in plasma, pharmacokinetic modeling, and dosing of busulfan was designed. The methods and results of the first 2 rounds of this proficiency testing are described herein. A novel method was developed to stabilize busulfan in N,N-dimethylacetamide, which allowed shipping of the proficiency samples without dry ice. In each round, participating laboratories reported their results for 2 proficiency samples (one low and one high busulfan concentrations) and a theoretical case assessing their pharmacokinetic modeling and dose recommendations. All participants were blinded to the answers; descriptive statistics were used to evaluate their overall performance. The guidelines suggested that answers within ±15% for busulfan concentrations and ±10% for busulfan plasma exposure and dose recommendation were to be considered accurate. Of the 4 proficiency samples evaluated, between 67% and 85% of the busulfan quantitation results were accurate (ie, within 85%-115% of the reference value). The majority (88% round #1; 71% round #2) of the dose recommendation answers were correct. A proficiency testing program by which laboratories are alerted to inaccuracies in their quantitation, pharmacokinetic modeling, and dose recommendations for busulfan in hematopoietic cell transplant recipients was developed. These rounds of proficiency testing suggests that additional educational efforts and proficiency rounds are needed to ensure appropriate busulfan dosing.

Validation of an UHPLC-MS/MS Method for the Determination of Malachite Green, Leucomalachite Green, Crystal Violet, and Leucocrystal Violet in Shrimp, Fish, and Salmon Muscle Using a Modified QuEChERS Approach

A quantitative and confirmatory method for detecting the presence of triphenylmethane dyes in shrimp muscle using ultra-high performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) and a quick, easy, cheap, effective, rugged and safe (QuEChERS) extraction approach was validated. The method exhibited linearity and selectivity and the coefficient of determination (R2) was higher than 0.95 for all studied analytes. Limits of detection (LODs) varied from 0.32 to 0.44 µg kg-1 and the limit of quantification (LOQ) was determined to be 0.5 µg kg-1 for all studied analytes. The trueness, precision, decision limits (CCα), detection capability (CCβ) and uncertainty presented adequate performance. In addition to the validation in shrimp muscle, fish and salmon muscle were also satisfactory validated as an extension of scope. The suitability of the proposed method was also evaluated through an interlaboratory proficiency test, in which satisfactory results were obtained. The fully validated method is thus suitable for the analysis of triphenylmethane dyes in shrimp, fish, and salmon muscle.