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Introduction: This study presents a longitudinal analysis of external quality assessment (EQA) results for erythropoietin (EPO) determinations conducted between 2017 and 2022 with a continuously increasing number of participating laboratories. The aim of this work was to evaluate participant performance and methodological aspects.Methods: In each of the eleven EQA surveys, a blinded sample set of lyophilized human serum containing one sample with lower EPO concentrations (L) and one with higher EPO concentrations (H) was sent to the participating laboratories.Results: A total of 1,256 measurements were included. The median (interquartile range) fraction of participants not meeting the criteria of acceptance set at 20% around the robust mean of the respective survey was 9.5% (6.1%–10.7%) (sample L) and 9.1% (5.8%–11.8%) (sample H) but lacked a clear trend in the observed period. Some surveys exhibited unusually high interlaboratory variation, suggesting interfering components in the EQA samples. Different immunological methods and reagent manufacturers also showed variability in measurement outcomes to some extent.Conclusion: These findings highlight the need for continuous quality assessment in EPO measurements to ensure patient safety and identify areas for further research and investigation.

In the present experiment, the significance of cultivar (convention-al and coloured) and of the application of the soil fertility enhancer UGmax on health-promoting properties of carrot roots subjected to the freezing process of carrot cubes after water blanching was investigated. The selection of cultivar turned out to be highly signif-icant with respect to the development of health-promoting properties of carrot roots. The highest antioxidant properties were found in the purple cultivar ‘Deep Purple’. Its mean antioxidant capacity accounted for 5.31 mmol Fe+2 · kg–1 f.m. Essential for health-promoting properties were the contents of anthocyanins (R2 = 0.83), chlorogenic acid (R2 = 0.81) and total polyphenolics (R2 = 0.71). The application of the biological agent UGmax improved the qual-ity of carrot significantly, increasing the content of total carotenoids and reducing the losses of ascorbic acid during processing. The freezing process negatively influenced the antioxidative properties of carrot irrespective of cultivar and applied agro-technique (use of UGmax), especially in the case of water-soluble antioxidants such as anthocyanins and ascorbic acid.

W artykule przedstawiono metodę doświadczalną szacowania niepewności wyniku pomiaru związanej z poborem i przygotowaniem próbek do badań w laboratorium chemicznym. Szacowania niepewności wyników pomiaru zawartości pierwiastków w próbkach rzeczywistych dokonano metodą oznaczania precyzji z użyciem analizy wariancji ROBUST ANOVA. Przykładowe badania próbek gleby prowadzone były w Laboratorium Instytutu Ochrony Środowiska - Państwowego Instytutu Badawczego. Metoda doświadczalna szacowania niepewności wyników pomiaru pozwala na szybkie i stosunkowo proste szacowanie wszystkich źródeł niepewności dotyczących pobierania i przygotowania próbek do badań w laboratorium chemicznym.

Purpose Accurate and precise measurements of creatinine are necessary to evaluate changes in kidney function related to a decreased glomerular filtration rate (GFR). When serial measurements of creatinine are monitored in an individual, it is useful to know what magnitude of an analytical change in creatinine indicates a true physiologic/biologic change in plasma creatinine that might warrant clinical intervention. Methods We compared results between three different methods for creatinine using large chemistry analyzers, two based on alkaline picrate (AP1 and AP2), and one based on dry-slide enzymatic conversion (ENZ). On each of three different segments or days of the study spaced 1–2 months apart, we selected 10 different plasma samples having creatinine concentrations ranging from about 0.5 mg/dL to 4.5 mg/dL (44 to 400 μmol/L). Each sample was analyzed in triplicate on each of two same-model analyzers at each institution, then from this data we determined the precision of each model of analyzer. The within-instrument precision of each analyzer was evaluated from the differences between the triplicate results on each sample by each analyzer (mean and SD of the differences). The between-instrument precision was evaluated as the differences between results on the same sample (1, 2, 3, etc.) analyzed on different analyzers of the same model (A and B). This between-analyzer precision data was used to determine both the range and mean ± 2SD of the differences that could be used to indicate that greater changes in creatinine concentrations would represent a biologic change. Results The within-instrument precision was best for the ENZ method in comparison to the two alkaline picrate rate methods. The between-instrument precision of the 90 consecutive measurements (30 samples × triplicate analyses) between the same-model analyzers were (mean and SD of differences in mg/dL): − 0.018 and 0.029 (ENZ); 0.016 and 0.11 (AP1), and − 0.058 and 0.071 (AP2). Conclusions While all three of the creatinine methods studied had good precision, the ENZ method had the best precision, such that a change of 0.07 mg/dL (6 μmol/L) in serial creatinine concentrations up to 1.5 mg/dL on a patient could indicate a biologic change had occurred. For the alkaline picrate methods, a measured change of creatinine of 0.23 mg/dL for AP1 or 0.11 mg/dL for AP2 would indicate that a physiologic change in serum/plasma creatinine has occurred. While a definite biologic change may simply represent daily variations, detecting a biologic change in creatinine more rapidly could impact the ability of creatinine to detect early and clinically significant changes in renal function. [ABSTRACT FROM AUTHOR]

Copyright of Ochrona Srodowiska i Zasobów Naturalnych is the property of Sciendo and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Ochrona Srodowiska i Zasobów Naturalnych is the property of Sciendo and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Ochrona Srodowiska i Zasobów Naturalnych is the property of Sciendo and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Purpose: To predict precision and other performance characteristics of chromatographic purity methods, which represent the most widely used form of analysis in the biopharmaceutical industry. Methods: We have conducted a comprehensive survey of purity methods, and show that all performance characteristics fall within narrow measurement ranges. This observation was used to develop a model called Uncertainty Based on Current Information (UBCI), which expresses these performance characteristics as a function of the signal and noise levels, hardware specifications, and software settings. Results: We applied the UCBI model to assess the uncertainty of purity measurements, and compared the results to those from conventional qualification. We demonstrated that the UBCI model is suitable to dynamically assess method performance characteristics, based on information extracted from individual chromatograms. Conclusions: The model provides an opportunity for streamlining qualification and validation studies by implementing a 'live validation' of test results utilizing UBCI as a concurrent assessment of measurement uncertainty. Therefore, UBCI can potentially mitigate the challenges associated with laborious conventional method validation and facilitates the introduction of more advanced analytical technologies during the method lifecycle. [ABSTRACT FROM AUTHOR]

The measurement uncertainty was estimated for the determination of sulfur content in petroleum and petroleum products according to the recommendations of the EURACHEM/CITAC Guide and ―Guide to the expression of uncertainty in measurement (GUM)‖. The major components contributing to their uncertainties were the amount of sulfur in the test sample and the method precision, based on the equation to calculate the measurand from the intermediate values. Consequently, the concen-tration of sulfur in the used CRM ERM – EF 213 (certified value 9.10.8 mg kg-1) with it expanded uncertainty was 9.84.0 mg kg-1, which was acceptable to support the successful application of the analytical method. The method precision gave the largest contribution to the overall combined uncertainty of sulfur concentration. [ABSTRACT FROM AUTHOR]

Abstract: The required performance of an analytical method depends on the purpose for which it will be used. As a methodology matures, it may find new application, and the performance demands placed on the method can increase. Sedimentation velocity analytical ultracentrifugation (SV-AUC) has a long and distinguished history with important contributions to molecular biology. Now the technique is transitioning into industrial settings, and among them, SV-AUC is now used to quantify the amount of protein aggregation in biopharmaceutical protein products, often at levels less than 1% of the total protein mass. In this paper, we review recent advances to SV methodology which have been shown to improve quantitation of protein aggregation. Then we discuss the performance of the SV method in its current state, with emphasis on the precision and quantitation limit of the method, in the context of existing industrial guidance on analytical method performance targets for quantitative methods. [Copyright &y& Elsevier]

We sampled 92 wetlands from four different basins in the United States to quantify observer repeatability in rapid wetland condition assessment using the Delaware Rapid Assessment Protocol (DERAP). In the Inland Bays basin of Delaware, 58 wetland sites were sampled by multiple observers with varying levels of experience (novice to expert) following a thorough training workshop. In the Nanticoke (Delaware/Maryland), Cuyahoga (Ohio), and John Day (Oregon) basins, 34 wetlands were sampled by two expert teams of observers with minimal protocol training. The variance in observer to observer scoring at each site was used to calculate pooled standard deviations (SDpool), coefficients of variation, and signal-to-noise ratios for each survey. The results showed that the experience level of the observer had little impact on the repeatability of the final rapid assessment score. Training, however, had a large impact on observer to observer repeatability. The SDpool in the Inland Bay survey with training (2.2 points out of a 0–30 score) was about half that observed in the other three basins where observers had minimal training (SDpool = 4.2 points). Using the results from the survey with training, we would expect that two sites assessed by different, trained observers who obtain DERAP scores differing by more than 4 points are highly likely to differ in ecological condition, and that sites with scores that differ by 2 or fewer points are within variability that can be attributed to observer differences. [ABSTRACT FROM AUTHOR]

Abstract: The measurement uncertainties (MUs) were estimated for the determination of methamphetamine (MA) and its main metabolite, amphetamine (AP) at the low concentrations (around the cut-off value of MA) in human hair according to the recommendations of the EURACHEM/CITAC Guide and “Guide to the expression of uncertainty in measurement (GUM)”. MA and AP were extracted by agitating hair with 1% HCl in methanol, followed by derivatization and quantification using GC–MS. The major components contributing to their uncertainties were the amount of MA or AP in the test sample, the weight of the test sample and the method precision, based on the equation to calculate the mesurand from intermediate values. Consequently, the concentrations of MA and AP in the hair sample with their expanded uncertainties were 0.66±0.05 and 1.01±0.06ng/mg, respectively, which were acceptable to support the successful application of the analytical method. The method precision and the weight of the hair sample gave the largest contribution to the overall combined uncertainties of MA and AP, for each. [Copyright &y& Elsevier]