1,721,049 research outputs found
Relevant criteria for the selection of cryotubes. Experiences from the German National Cohort
No full textMeasurement repeatability profiles of eight frequently requested measurands in clinical chemistry determined by duplicate measurements of patient samples
No full textMeasurement uncertainties in clinical chemistry are commonly regarded as heteroscedastic - having a constant relative standard deviation irrespective of the concentration of the measurand. The uncertainty is usually determined at two concentrations using stabilized control materials and assumed to represent the analytical goal. The purpose of the present study was to use duplicates of unselected patient samples to calculate the absolute and relative repeatability component of the intra-laboratory measurement uncertainty from duplicates, using the Dahlberg formula and analysis of variance components. Estimates were made at five different concentration intervals of ALT, AST, Calcium, Cholesterol, Creatinine, CRP, Triglycerides and TSH covering the entire concentration interval of the patient cohort. This partioning allows detailing their repeatability profiles. The calculations of the profiles were based on randomly selected results from sets of duplicates ranging from 12,000 to 65,000 pairs. The repeatability of the measurands showed substantial variability within the measuring interval. Therefore, characterizing imprecision profiles as purely homo- or heteroscedastic or by a single number may not be optimal for the intended use. The present data make a case for nuancing the evaluation of analytical goals and minimal differences of measurement results by establishing uncertainty profiles under repeatability conditions, using natural patient samples.Funding Agencies|Karolinska university laboratory; County council of Ostergotland</p
Free light chain kappa and the polyspecific immune response in MS and CIS – Application of the hyperbolic reference range for most reliable data interpretation
No full textStrengthening Epidemic Management: A German Perspective on Establishing Networked Epidemic Panels from Existing Population Studies
No full text<p><span>During the COVID-19 pandemic, many countries, including Germany, lacked of a nationwide network of adaptive epidemic panels representing the general population. Such a network of epidemic panels could have swiftly conveyed estimates of current infection incidence, immunity, or contact pattern to analytical platforms for modelling the infection process and to decision-makers in a timely manner. </span></p>
<p><span>In this position paper, we argue that the existing population studies, cohorts and infrastructures in Germany offer an excellent foundation for establishing a network structure to form epidemic panels. The motivations, prerequisites, and characteristics of this network structure are discussed and elucidated using a successful example of such a network.</span></p>
<p><span>In our pioneering project (Immunebridge), we harmonised data and analysed blood samples from nine population-/hospital-based studies (n=33,637) to provide estimates for protection levels against severe COVID-19 between June and November 2022. The project was structured to enable early ad-hoc feedback to consortia of a newly established modelling network for severe infectious diseases (MONID) from August 2022 onwards. For this, aggregated data were presented in a model-usable format in two interim reports in 2022 to support the MONID consortia.</span></p>
<p><span>Collaboration within this network of epidemic panels should be expanded to involve as many relevant stakeholders as possible.</span></p>
Variability of Thyroid Measurements from Ultrasound and Laboratory in a Repeated Measurements Study
No full textBackground: Variability of measurements in medical research can be due to different sources. Quantification of measurement errors facilitates probabilistic sensitivity analyses in future research to minimize potential bias in epidemiological studies. We aimed to investigate the variation of thyroid-related outcomes derived from ultrasound (US) and laboratory analyses in a repeated measurements study. Subjects and Methods: Twenty-five volunteers (13 females, 12 males) aged 22–70 years were examined once a month over 1 year. US measurements included thyroid volume, goiter, and thyroid nodules. Laboratory measurements included urinary iodine concentrations and serum levels of thyroid-stimulating hormone (TSH), free triiodothyronine (fT3), free thyroxine (fT4), and thyroglobulin. Variations in continuous thyroid markers were assessed as coefficient of variation (CV) defined as mean of the individual CVs with bootstrapped confidence intervals and as intraclass correlation coefficients (ICCs). Variations in dichotomous thyroid markers were assessed by Cohen’s kappa. Results: CV was highest for urinary iodine concentrations (56.9%), followed by TSH (27.2%), thyroglobulin (18.2%), thyroid volume (10.5%), fT3 (8.1%), and fT4 (6.3%). The ICC was lowest for urinary iodine concentrations (0.42), followed by fT3 (0.55), TSH (0.64), fT4 (0.72), thyroid volume (0.87), and thyroglobulin (0.90). Cohen’s kappa values for the presence of goiter or thyroid nodules were 0.64 and 0.70, respectively. Conclusion: Our study provides measures of variation for thyroid outcomes, which can be used for probabilistic sensitivity analyses of epidemiological data. The low intraindividual variation of serum thyroglobulin in comparison to urinary iodine concentrations emphasizes the potential of thyroglobulin as marker for the iodine status of populations
Integrated biobanks facilitate high-quality collection and analysis of liquid biomaterials
No full textEvaluation of the AFIAS-1 thyroid-stimulating hormone point of care test and comparison with laboratory-based devices
No full textAbstract Objectives Thyroid-stimulating hormone (TSH) is the routine primary screening test to assess thyroid function and rapid measurement of TSH levels is highly desirable especially in emergency situations. In the present study, we compared the analytical performance of a commercially available point-of-care test (AFIAS-1) and five laboratory-based systems. Methods Left over material of 60 patient plasma samples was collected from patient care and used in the respective assay. For statistical analysis of the produced data Bland-Altman and Passing-Bablok regression analysis were applied. Results Good correlation (r=0.982 or higher) was found between all devices. Slopes from regression analysis ranged from 0.972 (95% CI: 0.927–1.013) to 1.276 (95% CI: 1.210–1.315). Among the compared devices, imprecision was high in terms of coefficient of variation (CV=10.3%) for low TSH concentrations and lower (CV=7.3%) for high TSH concentrations. Independent of the method used, we demonstrated a poor standardization of TSH assays, which might impact clinical diagnosis e.g. of hyperthyreosis. Conclusions This study shows that the point-of-care (POC) test AFIAS-1 can serve as an alternative to laboratory-based assays. In addition the data imply that better standardization of TSH measurements is needed.Abstract Objectives Thyroid-stimulating hormone (TSH) is the routine primary screening test to assess thyroid function and rapid measurement of TSH levels is highly desirable especially in emergency situations. In the present study, we compared the analytical performance of a commercially available point-of-care test (AFIAS-1) and five laboratory-based systems. Methods Left over material of 60 patient plasma samples was collected from patient care and used in the respective assay. For statistical analysis of the produced data Bland-Altman and Passing-Bablok regression analysis were applied. Results Good correlation (r=0.982 or higher) was found between all devices. Slopes from regression analysis ranged from 0.972 (95% CI: 0.927–1.013) to 1.276 (95% CI: 1.210–1.315). Among the compared devices, imprecision was high in terms of coefficient of variation (CV=10.3%) for low TSH concentrations and lower (CV=7.3%) for high TSH concentrations. Independent of the method used, we demonstrated a poor standardization of TSH assays, which might impact clinical diagnosis e.g. of hyperthyreosis. Conclusions This study shows that the point-of-care (POC) test AFIAS-1 can serve as an alternative to laboratory-based assays. In addition the data imply that better standardization of TSH measurements is needed
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