Interlaboratory Comparison Research Articles

Validation and interlaboratory comparison of anticoagulant rodenticide analysis in animal livers using ultra-performance liquid chromatography-mass spectrometry.

Anticoagulant rodenticides (ARs) are used to control rodent populations. Poisoning of non-target species can occur by accidental consumption of commercial formulations used for rodent control. A robust method for determining ARs in animal tissues is important for animal postmortem diagnostic and forensic purposes. We evaluated an ultra-performance liquid chromatography coupled with mass spectrometry (UPLC-MS) method to quantify 8 ARs (brodifacoum, bromadiolone, chlorophacinone, coumachlor, dicoumarol, difethialone, diphacinone, warfarin) in a wide range of animal (bovine, canine, chicken, equine, porcine) liver samples, including incurred samples. We further evaluated UPLC-MS in 2 interlaboratory comparison (ILC) studies; one an ILC exercise (ICE), the other a proficiency test (PT). The limits of detection of UPLC-MS were 0.3-3.1 ng/g, and the limits of quantification were 0.8-9.4 ng/g. The recoveries obtained using UPLC-MS were 90-115%, and relative SDs were 1.2-13% for each of the 8 ARs for the 50, 500, and 2,000 ng/g spiked liver samples. The overall accuracy from the laboratories participating in the 2 ILC studies (4 and 11 laboratories for ICE and PT studies, respectively) were 86-118%, with relative repeatability SDs of 3.7-11%, relative reproducibility SDs of 7.8-31.2%, and Horwitz ratio values of 0.5-1.5. Via the ILC studies, we verified the accuracy of UPLC-MS for AR analysis in liver matrices and demonstrated that ILC can be utilized to evaluate performance characteristics of analytical methods.

Reexamining Compliance with Gastric Emptying Scintigraphy Guidelines: An Updated Analysis of the Intersocietal Accreditation Commission Database.

Many variables can influence the results of gastric emptying scintigraphy (GES). A lack of standardization causes variability, limits comparisons, and decreases the credibility of the study. To increase standardization, in 2009 the Society of Nuclear Medicine and Molecular Imaging (SNMMI) published a guideline for a standardized, validated GES protocol for adults based on a 2008 consensus document. Laboratories must closely follow the consensus guideline to provide valid and standardized results as an incentive to achieve consistency in patient care. As part of the accreditation process, the Intersocietal Accreditation Commission (IAC) evaluates compliance with such guidelines. The rate of compliance with the SNMMI guideline was assessed in 2016 and showed a substantial degree of noncompliance. The aim of this study was to reassess compliance with the standardized protocol across the same cohort of laboratories, looking for changes and trends. Methods: The IAC nuclear/PET database was used to extract GES protocols from all laboratories applying for accreditation from 2018 to 2021, 5 y after the initial assessment. The number of labs was 118 (vs. 127 in the initial assessment). Each protocol was again evaluated for compliance with the methods described in the SNMMI guideline. The same 14 variables were assessed in a binary fashion: patient preparation (4 variables-types of medications withheld, withholding of these medication for 48 h, blood glucose ≤ 200 mg/dL, blood glucose recorded), meal (5 variables-use of consensus meal, nothing by mouth for 4 h or more, meal consumed within 10 min, documentation of percentage of meal consumed, meal labeled with 18.5-37 MBq [0.5-1.0 mCi]), acquisition (2 variables-anterior and posterior projections obtained, imaging each hour out to 4 h), and processing (3 variables-use of the geometric mean, decay correction of data, and measurement of percentage retention). Results: Protocols from the 118 labs demonstrated that compliance is improving in some key areas but remains suboptimal in others. Overall, labs were compliant with an average of 8 of the 14 variables, with a low of 1-variable compliance at 1 site, and only 4 sites compliant with all 14 variables. Nineteen sites met an 80% threshold for compliance (11+ variables). The variable with the highest compliance was the patient's taking nothing by mouth for 4 h or more before the exam (97%). The variable with the lowest compliance was the recording of blood glucose values (3%). Notable areas of improvement include the use of the consensus meal, now 62% versus previously only 30% of labs. Greater compliance was also noted with measurement of retention percentages (instead of emptying percentages or half-times), with compliance by 65% of sites versus only 35% 5 y prior. Conclusion: Almost 13 y after the publication of the SNMMI GES guidelines, there is improving but still suboptimal protocol adherence among laboratories applying for IAC accreditation. Persistent variation in the performance of GES protocols may significantly affect patient management, as results may be unreliable. Using the standardized GES protocol permits interpretation of results in a consistent manner that allows interlaboratory comparisons and fosters acceptance of the test validity by referring clinicians.

Toxic or not toxic? The specifications of the standard ISO 10993-5 are not explicit enough to yield comparable results in the cytotoxicity assessment of an identical medical device.

Medical device manufacturers are obliged to prove the biocompatibility of their products when they come into contact with the human body. The requirements for the biological evaluation of medical devices are specified by the international standard series ISO 10993. Part five of this series describes the performance of in vitro cytotoxicity tests. This test evaluates the effects of medical device use on cell health. The existence of the specific standard suggests that the tests will produce reliable and comparable results. However, the ISO 10993-5 offers wide latitude in the test specifications. In the past, we noticed inconsistencies of the results from different laboratories. To determine if the specifications of the standard ISO 10993-5 are explicit to ensure the comparability of test results and, if not, identify potential influencing factors. An interlaboratory comparison was conducted for the in vitro cytotoxicity test according to ISO 10993-5. Fifty-two international laboratories evaluated the cytotoxicity for two unknown samples. One was polyethylene (PE) tubing, which is expected to be non-cytotoxic and the other was polyvinyl chloride (PVC) tubing, for which a cytotoxic potential was presumed. All laboratories were asked to perform an elution test with predefined extraction specifications. The other test parameters were freely chosen by the laboratories according to the guidelines set by the standard. To our surprise only 58 percent of the participating laboratories identified the cytotoxic potential of both materials as expected. Particularly for PVC a considerable variation of the results between the laboratories was observed [mean = 43 ± 30 (SD), min = 0, max = 100]. We showed that ten percent serum supplementation to the extraction medium, as well as longer incubation of the cells with the extract, greatly increased the test sensitivity for PVC. The results clearly show that the specifications set by the ISO 10993-5 are not explicit enough to obtain comparable results for an identical medical device. To set requirements that ensure reliable cytotoxicity assessments, further research will be necessary to identify the best test conditions for specific materials and/or devices and the standard needs to be revised accordingly.

How and when to measure pH in IVF culture media: validation of a portable blood gas analyzer in two IVF culture dishes for time lapse and conventional incubators.

Maintaining a stable pH at optimal level in human embryo culture media is crucial for embryo development but poses a challenge for all IVF laboratories. We validate analytically reliable conditions for pH measurement that are as close as possible to the embryo microenvironment during IVF. This was a multicentric study. A Siemens EPOC portable blood gas analyzer was used. The analytical validation was carried out under the culture medium (Global Total HSA®) conditions of use (microdroplets, under oil overlay, in a IVF incubator with (EmbryoScope®) or without a time lapse system (K system G210+®) and using IVF dishes. The validation included repeatability ("within-run" precision), total precision (between-day precision), trueness based on inter-laboratory comparison, inaccuracy based on external quality assessment and comparison to the reference technique. We also assessed the pre-analytical medium incubation time required to obtain a target value. A measurement after an incubation period of 24 to 48 h is more representative of the pH to which the embryo will be exposed throughout the culture. The "within-run" and "between-day" precision show very low coefficients of variation (CV%): 0.17 to 0.22% and 0.13 to 0.34%, respectively, with IVF culture media. Trueness (% bias) range from - 0.07 to - 0.03%. We demonstrate good correlation between EPOC and reference pH electrode with an overestimation of 0.03 pH units of EPOC. Our method demonstrates good analytical performance for IVF laboratories wishing to implement a robust quality assurance system to monitor pH in embryo culture media. Compliance with stringent pre-analytical and analytical conditions is essential.

Mineral Crushing Methods for Noble Gas Analyses of Fluid Inclusions

Noble gases are frequently probed for investigating fluid inclusions in minerals to unravel rock-forming processes through time. Over the last decades, heating and crushing have been the two main methods applied for noble gas extraction from fluid inclusions in ultrahigh vacuum (about 10-9 mBar). The heating of minerals or pieces of bulk rock causes the release of noble gases from both fluid inclusions and the mineral or rock matrix, the latter due to temperature-dependent mineral dehydration. Crushing of minerals only affects fluid inclusions and allows a release of noble gases at room temperature with minor contributions from the mineral matrix. This review describes different ultravacuum crushing techniques for noble gas analysis from fluid inclusions. It examines the technical details and operational conditions of each crushing system as well as methods to prepare samples prior to crushing. Crushing systems were found to have unique designs across the different laboratories reviewed; they include single or multiple sample loadings and manual, magnetic, or hydraulic operation of the crushing pistons. Due to the small amounts of noble gases released, the technology requires several mg to a few grams of rock material to achieve a measurement of all stable noble gas isotopes in a single fluid inclusion. While theoretically all stable noble gas isotopes are of interest, the elements and isotopes reported in different studies vary widely and reference materials as well as laboratory intercomparisons are lacking. The review includes applications on the origins of magmatic rocks and geochemical processes in the Earth’s mantle, the origin and chemical composition of deep crustal fluids and how these contribute to the formation of minerals of economic interest, and paleoclimate studies based on speleothems.

Interlaboratory comparison of battery impedance analyzers calibration

The paper reports a results of series of interlaboratory comparisons of low impedance measurements at frequencies relevant for electrochemical impedance spectroscopy (EIS) of commercial lithium-ion cells. Two comparisons are presented. The first, bilateral comparison has focused on low impedance standards calibration in a full complex plane using digital sampling setups. The second comparison has focused on calibration and use of commercial 4-terminal battery EIS meters. Both comparisons have covered the impedance range from 50μ℧ to 100m℧ across the full complex plane in a frequency range from 0.01Hz up to 5kHz. Finally, the paper summarizes practices identified as critical for achieving measurement compatibility among various labs.

Dimensional XCT comparison campaign on an aluminium object

An x-ray computed tomography (XCT) interlaboratory comparison campaign, involving an aluminium-machined object, whose dimensions (92 × 78 × 63 mm3) are significant for a 225 kV XCT system, was performed for the purpose of investigating the performances of industrial XCT systems for dimensional measurements in terms of accuracy, i.e. precision and trueness, and to evaluate the influence of the measurement protocol (i.e. measurement strategy), of the operator and of the software on the results by comparison to reference measurements. In this campaign, we came to the conclusion that the measurement strategy is predominant, except for distance; that the measurement process is affected by the operator only for cylindricity and coaxiality; that there is no or little influence of the software except for coaxiality and position; and that a volumetric Gaussian filter allows to improve the measurements only for some participants’ measurements Furthermore, different behaviours, in terms of precision and trueness, are observed depending on the type of measurands when performed by different operators. The diameter measurements are reproducible with XCT, lower than 30 µm which corresponds to a subvoxelic factor of 2.5 and the trueness is lower than 22 µm. The distance measurement is also reproducible with XCT, 15 µm which corresponds to a subvoxelique factor of 4.9 and the trueness is 8 µm. For these mesurands, their measurements do not depend on the used XCT system. However, the XCT reproducibility for cylindricity, coaxiality and position is worse as well as of the trueness except for the position which has a trueness of 1 µm. The process measurement should be revised regarding cylindricity and coaxiality measurements. Finally, overall, the ability of the participants to perform measurements with XCT, whatever their system, is statistically comparable except for a few measurements.

Harmonizing nanomaterial exposure methodologies in ecotoxicology: the effects of two innovative nanoclays in the freshwater microalgae Raphidocelis subcapitata

Layered double hydroxides (LDHs) are innovative nanomaterials (NMs) with a typical nanoclay structure (height <40 nm) consisting of layers of metallic cations and hydroxides stabilized by anions and water molecules. Upon specific triggers, anions can exchange by others in the surrounding environment. Due to this stimuli-responsive behavior, LDHs are used as carriers of active ingredients in the industrial or pharmaceutical sectors. Available technical guidelines to evaluate the ecotoxicity of conventional substances do not account for the specificities of NMs, leading to inaccuracies and uncertainty. The present study aimed to assess two different exposure methodologies (serial dilutions of the stock dispersion vs. direct addition of NM powder to each concentration) on the ecotoxicological profile of different powder grain sizes of Zn–Al LDH-NO3 and Cu–Al LDH-NO3 (bulk, <25, 25–63, 63–125, 125–250, and >250 µm) in the growth of the freshwater microalgae Raphidocelis subcapitata. Results revealed that the serial dilutions methodology was preferable for Zn–Al LDH-NO3, whereas for Cu–Al LDH-NO3 both methodologies were suitable. Thus, the serial dilutions methodology was selected to assess the ecotoxicity of different grain sizes for both LDHs. All Zn–Al LDH-NO3 grain sizes yielded similar toxicity, while Cu–Al LDH-NO3 powders with smaller grain sizes caused a higher effect on microalgae growth; thus, grain size separation might be advantageous for future applications of Cu–Al LDH-NO3s. Considering the differences between exposure methodologies for the Zn–Al LDH-NO3, further research involving other NMs and species must be carried out to achieve harmonization and validation for inter-laboratory comparison.

Successful Detection of Delta and Omicron Variants of SARS-CoV-2 by Veterinary Diagnostic Laboratory Participants in an Interlaboratory Comparison Exercise.

Throughout the COVID-19 pandemic, veterinary diagnostic laboratories have tested diagnostic samples for SARS-CoV-2 both in animals and over 6 million human samples. An evaluation of the performance of those laboratories is needed using blinded test samples to ensure that laboratories report reliable data to the public. This interlaboratory comparison exercise (ILC3) builds on 2 prior exercises to assess whether veterinary diagnostic laboratories can detect Delta and Omicron variants spiked in canine nasal matrix or viral transport medium. The ILC organizer was an independent laboratory that prepared inactivated Delta variant at levels of 25 to 1000 copies per 50 µL of nasal matrix for blinded analysis. Omicron variant at 1000 copies per 50 µL of transport medium was also included. Feline infectious peritonitis virus (FIPV) RNA was used as a confounder for specificity assessment. Fourteen test samples were prepared for each participant. Participants used their routine diagnostic procedures for RNA extraction and real-time reverse transcriptase-PCR. Results were analyzed according to International Organization for Standardization (ISO) 16140-2:2016. Overall, laboratories demonstrated 93% detection for Delta and 97% for Omicron at 1000 copies per 50 µL. Specificity was 97% for blank samples and 100% for blank samples with FIPV. No differences in Cycle Threshold (Ct) values were significant for samples with the same virus levels between N1 and N2 markers, nor between the 2 variants. The results indicated that all ILC3 participants were able to detect both Delta and Omicron variants. The canine nasal matrix did not significantly affect SARS-CoV-2 detection.

Zinc Isotope Measurement by MC‐ICP‐MS in Geological Certified Reference Materials

Here we present an analytical method for Zinc (Zn) isotopic measurements using “standard‐sample bracketing” on a Nu Sapphire multi‐collector inductively coupled plasma‐mass spectrometer. The effects of Zn mass fraction and HNO3 molarity mismatch between the standard and the sample, as well as the presence of matrix elements have been evaluated. Long‐term reproducibility of better than ±0.03‰ for δ66Zn (2s) was routinely obtained. Accurate measurements were achieved when CNi/CZn &lt; 0.001, CTi/CZn &lt; 0.03, CBa/CZn &lt; 0.05, CNa/CZn and CAl/CZn &lt; 0.5, CMg/CZn &lt; 0.1, CFe/CZn &lt; 5 and CCu/CZn as well as CCd/CZn &lt; 10. High‐precision Zn isotopic determination were performed on twenty‐one widely available geological certified reference materials, with an overall range of ~ 0.62‰ (0.15 to 1.07‰), which is nearly twenty times the current analytical precision (0.03), and the results are in agreement with most previously published data within 2s. Among them, δ66ZnJMC 3‐0749L of eleven geological certified reference materials are reported for the first time: 0.22 ± 0.03‰ (dolerite, DR‐N), 0.23 ± 0.02‰ (gabbro, GSR‐10), 0.20 ± 0.04‰ (microgabbro, PM‐S), 0.15 ± 0.02‰ (andesite, GSR‐2), 0.22 ± 0.08‰ (diorite, GSR‐9), 0.19 ± 0.07‰ (syenite, GSR‐7), 0.30 ± 0.06‰ (granite, GSR‐1), 0.25 ± 0.00‰ (rhyolite, GSR‐11), 0.37 ± 0.01‰ (shale, GSR‐5), 0.21 ± 0.03‰ (limestone, GSR‐6) and 0.20 ± 0.03‰ (hornblendite, GSR‐15). The novel Zn isotopic data from these certified reference materials can be used for future interlaboratory comparisons.

Transferability and reproducibility of exposed air-liquid interface co-culture lung models

BackgroundThe establishment of reliable and robust in vitro models for hazard assessment, a prerequisite for moving away from animal testing, requires the evaluation of model transferability and reproducibility. Lung models that can be exposed via the air, by means of an air-liquid interface (ALI) are promising in vitro models for evaluating the safety of nanomaterials (NMs) after inhalation exposure. We performed an inter-laboratory comparison study to evaluate the transferability and reproducibility of a lung model consisting of the human bronchial cell line Calu-3 as a monoculture and, to increase the physiologic relevance of the model, also as a co-culture with macrophages (either derived from the THP-1 monocyte cell line or from human blood monocytes). The lung model was exposed to NMs using the VITROCELL® Cloud12 system at physiologically relevant dose levels. ResultsOverall, the results of the 7 participating laboratories are quite similar. After exposing Calu-3 alone and Calu-3 co-cultures with macrophages, no effects of lipopolysaccharide (LPS), quartz (DQ12) or titanium dioxide (TiO2) NM-105 particles on the cell viability and barrier integrity were detected. LPS exposure induced moderate cytokine release in the Calu-3 monoculture, albeit not statistically significant in most labs. In the co-culture models, most laboratories showed that LPS can significantly induce cytokine release (IL-6, IL-8 and TNF-α). The exposure to quartz and TiO2 particles did not induce a statistically significant increase in cytokine release in both cell models probably due to our relatively low deposited doses, which were inspired by in vivo dose levels. The intra- and inter-laboratory comparison study indicated acceptable interlaboratory variation for cell viability/toxicity (WST-1, LDH) and transepithelial electrical resistance, and relatively high inter-laboratory variation for cytokine production. ConclusionThe transferability and reproducibility of a lung co-culture model and its exposure to aerosolized particles at the ALI were evaluated and recommendations were provided for performing inter-laboratory comparison studies. Although the results are promising, optimizations of the lung model (including more sensitive read-outs) and/or selection of higher deposited doses are needed to enhance its predictive value before it may be taken further towards a possible OECD guideline.

A New Method for Dead Time Calibration and a New Expression for Correction of WDS Intensities for Microanalysis.

Observed photon count rates must be corrected for detector dead time effects for accurate quantification, especially at high count rates. We present the "constant k-ratio" method, a new approach for calibrating dead time for wavelength dispersive spectrometers by measuring k-ratios as a function of beam current. The method is based on the observation that for a given emission line at a specific take-off angle and electron beam energy, the intensity ratio from two materials containing the element should remain constant as a function of beam current, if the dead time calibration is accurate. The method has the advantage that it does not rely on the linearity of the beam current picoammeter, yet also allows the analyst to evaluate the picoammeter linearity, another critical parameter in EPMA calibration. By simultaneously comparing k-ratios for all spectrometers, one can also ascertain k-ratio consensus, essential for inter-laboratory comparisons. We also introduce improved dead time expressions and provide best practices on how to perform these instrument calibrations using this new "constant k-ratio" method. These improvements enable quantitative analysis of major and minor elements with high accuracy at high beam currents, simultaneously with trace elements with high sensitivity, for point analyses and X-ray mapping.

THE STUDY OF METROLOGICAL CHARACTERISTICS OF THE OBTAINED SUBSTANCES OF FAT-SOLUBLE VITAMINS BY INTERLABORATORY COMPARISON TESTS

Relevance. This article discusses the possibility of using substances isolated from natural raw materials of fat-soluble vitamins retinol-palmitate (vitamin A), cholecalciferol (vitamin D3), tocopherol-acetet (vitamin E) in order to create domestic standard samples of approved type (SSS). The use of SSS in analytical practice, as well as in scientific research, makes it possible to ensure the accuracy and reliability of experimental results, to ensure the traceability of the result when performing analyses within the framework of repeatability and reproducibility (precision). The paper addresses issues related to the production and standardization of domestic pharmaceutical substances, as well as issues of standardization and conformity assessment of finished products of the pharmaceutical industry and other sectors of the national economy (food industry, agriculture, perfumery and cosmetics, the industry of production of goods for children's practice, etc.). The purpose of the work. To establish the quantitative content of fat-soluble vitamins A, D3, E, in the obtained substances claiming the status of SS with the approved type, as well as to determine their stability and uniformity by means of interlaboratory comparison tests (hereinafter referred to as ICT). Material and methods. The quantitative content of fat-soluble vitamins in the obtained substances was assessed by HPLC in 6 accredited analytical laboratories. The results were processed by evaluating the data provided for the presence of outliers and quasi-outliers using the Kohren, Grubbs and Mandel method. Results. The conducted studies under the comparison program showed that the results of the quantitative determination of the obtained vitamins are within the norms of the certified characteristic "Mass fraction of vitamin, %" in relation to the content of the determined characteristic in reference substances of imported production. Conclusions. As a result of the statistical data obtained, we have proved that the substances obtained from fat-soluble vitamins A, E, D3 comply with regulatory requirements based on the results of interlaboratory comparisons and can be recommended for the manufacture of domestic SS with the approval of their type, and it can also be assumed that the manufacturing processes of domestic and imported SS are harmonized. The quality of domestic SS is at an identical level with respect to foreign SS, but each is produced exclusively in the legal field of the manufacturer's state and is legitimate in its territory of application, which once again confirms the high need to create a domestic reference pharmaceutical base.

109 Inter- and Intra-Laboratory Comparison of 6 Dustiness Testing Methods: Towards the Development of an OECD Testing Guideline

Abstract Dustiness is a key parameter describing the ability of powder materials to generate dust during agitation. The main goal of this work was to generate and assess the scientific basis for the validation and applicability of 6 dustiness methods to nanomaterials, and development of a subsequent OECD testing guideline. Six dustiness methods (rotating drum, small rotating drum, continuous drop, vortex shaker, fluidizer and venturi) were subjected to an intra- and inter-laboratory comparison (ILC) in which 15 international laboratories participated. ILC tests were conducted for 6 materials (3 TiO2 and 3 SiO2) of different chemical natures and dustiness levels. Each participating laboratory conducted at least 3 replicates per material. Harmonization of procedures, methods and data treatment took place prior to testing. Results from the ILC were assessed considering the different reported metrics such as respirable mass and particle number dustiness index. Overall, the intralaboratory variability for the different methods and metrics was under 30%. Variation between laboratories was generally higher for respirable mass than particle number dustiness index. These variations were mostly attributed to differences in setups such as tubing length or instrumentation. All methods except the venturi, which was characteristic for presenting low differences between materials and opposed classification to the rest of the methods, showed relatively similar material ranking. For all methods and laboratories the calculated z-score (measure of the deviation of each laboratory from the true value) was &amp;lt;2 as based on ISO 13528, which indicates gratifying results. Funding: EU H2020 Research and Innovation Programme under Grant Agreement 814401.

97 Transferability and Reproducibility of Exposed Air-Liquid Interface co-Culture Lung Models

Abstract The establishment of reliable and robust in vitro models for hazard assessment, moving away from animal testing, requires evaluation of model transferability and reproducibility. Lung models that can be exposed via the air, by means of an air-liquid interface are promising in vitro models for evaluating the safety of nanomaterials (NMs) after inhalation exposure. We performed an inter-laboratory comparison study to evaluate the transferability and reproducibility of a lung model consisting of the human bronchial cell line Calu-3 as monoculture and, to increase the relevance of the model, also as co-culture with macrophages (derived from the THP-1 monocyte cell line or from human blood monocytes). Exposure employed the VITROCELL® Cloud12 system at physiologically relevant doses. Overall, the results of the seven participating laboratories are quite similar. No effects of lipopolysaccharide (LPS), quartz (DQ12) or titanium dioxide (TiO2) NM-105 exposure on cell viability and barrier integrity were seen in the monoculture and co-culture models. Most laboratories showed that LPS induced cytokine release in the co-culture models, but not the monoculture model. Exposure to DQ12 or TiO2 did not increase cytokine release, probably due to too low deposited doses. Interlaboratory variability indicated acceptable variation for cell viability measurements and relatively high variation for cytokine measurements. Based on the transferability and reproducibility of the model and its air exposure we are confident that, based on detailed SOPs, performing a new round of interlaboratory comparison, and increasing the deposited doses of NMs, these models may be taken further towards a possible OECD guideline.

Application of KU812 cells for assessing complement activation related effects by nano(bio)materials

Immunocompatibility issues related to nano(bio)materials, particularly liposomal formulations, involving activation of the complement system have been relatively well described however, they highlight the importance of preclinical evaluation of such interactions. These complement-mediated hypersensitivity reactions, in which basophils are implicated, are associated with complement activation-related pseudoallergy (CARPA). Ex vivo investigation of such events using primary basophils is technically challenging due to the relatively limited number of circulating basophils in peripheral blood. In the current work, the KU812 cell line has been applied as an in vitro model for basophil activation to investigate CARPA-related responses following exposure to test materials obtained from the REFINE consortium. To that end, we developed a standard operating procedure measuring a panel of cell-surface markers indicative of basophilic activation. Two laboratories performed the assays, demonstrating a clear difference in responses between liposomal and polymeric nano(bio)materials, while interlaboratory comparison of the standard operating procedure demonstrated reproducibility in results, between the two facilities. These results suggest the potential to use this protocol as a screening method for such responses however, validation using primary basophils is now warranted.

The interlaboratory comparisons role in the Ukrainian metrology system functioning

It is considered the usage of interlaboratory comparisons for the assuring of national metrology system functioning in the part of national measurement standards recognition (international standards comparisons), development and support the system of the units dissemination (the measurements methods evaluation and reference materials certification by interlaboratory experiment) and the calibration, testing and medical laboratories competence confirmation while their accreditation (proficiency testing). The information on valid European Proficiency Testing System EPTIS is presented. The programs for different types of laboratory studies are considered. The approaches to participants functioning evaluation are presented for the proficiency testing while calibration programs. The recommendations by international documents concerning laboratory activities monitoring reliability are presented.

Automation of evaluation of the interlaboratory comparisons results by means of software

The number of interlaboratory comparisons of measurement results increase, and the number of their participants requires providers to automate data processing procedures. The article is devoted to developing software for the calculation automation and display of interlaboratory comparisons results. The article analyzes the existing software and identifies its main shortcomings. Peculiarities of the application of En, z and ξ criteria are considered. Features of using the Python programming language for calculations and data display are described. Using the example of conducted interlaboratory comparisons, the possibilities of the developed software for automating calculations and data analysis, and displaying results, are demonstrated.

Interlaboratory test results comparisons for active and reactive energy meter

The article is dedicated to the organization and performance of bilateral interlaboratory comparisons of test results for active and reactive energy meter. Interlaboratory comparisons of test results are presented. Evaluation of the laboratory test results bias is provided by means of functioning statistics En criterion. Analysis and conclusions concerning laboratory competence are obtained.

The first total reflection X-ray fluorescence round-robin test of rat tissue samples: Preliminary results

The purpose of the study was performing a round-robin test for the element analysis of mammalian tissue samples using total reflection X-ray fluorescence (TXRF). To achieve this goal, the selected rat organs (kidney, heart, spleen and lung) were subjected to microwave digestion and, in the liquid form, were sent to four European laboratories participating in the inter-comparison investigation. There, using various commercially available TXRF spectrometers, their elemental composition was determined. The carried inter-laboratory comparisons involved macroelements with the concentration above 1000 μg/g (P, S and K) as well as microelements (Ca) and trace elements (Fe, Cu, Zn and Se) occurring, respectively, in the concentrations of 100–1000 μg/g and below 100 μg/g. The validation parameters such as the detection limits of the examined elements as well as the intra-day and inter-day precision were determined. To verify the variation in the results acquired in participating laboratories, for all measured elements, the inter-laboratory precision was evaluated. The data obtained by TXRF were also compared with the ones resulting from ICP-MS (Se) and ICP-OES analysis (P, S, K, Ca, Fe, Cu and Zn).The results obtained as part of the study confirmed the high usefulness of the TXRF method in the elemental analysis of animal tissues. As expected, the best results in terms of the examined validation parameters were obtained for elements with higher atomic numbers (Fe, Cu, Zn and Se). For these analytes, the round-robin test confirmed a good accuracy (around 100% for Fe, Cu, Zn) and precision (intra-day <6%, inter-day <12% and inter-laboratory <12%) what supports the use of TXRF for their determination in the mammalian tissue samples. The obtained results allowed, moreover, to indicate potential issues that require resolving in order to increase the usefulness of the method in case of the analysis of light elements such as P, S or K. It is worth mentioning here, inter alia, the improvement of the sample preparation procedures aiming at the reduction of self-absorption in its dried residue, optimization and/or unification of the sensitivity calibration and the spectra fitting procedures in particular laboratories.