177,641 research outputs found
Valutazione del sistema Capillarys 2 Flex Piercing per la misura dell'emoglobina A1c = Evaluation of the Capillarys 2 Flex Piercing system for the determination of hemoglobin A1c (HbA1c)
No full textThe Capillarys HbA1c kit implemented on the Capillarys 2 Flex Piercing platform uses capillary electrophoresis to separate
and quantify HbA1c in human blood. We performed an evaluation of this system by checking imprecision, relative bias
and robustness respect to the analysis of samples with variable total hemoglobin concentrations. Intra-assay CVs were
between 1.1% and 2.8% for HbA1c values between 35.8 mmol/mol and 96.4 mmol/mol. Inter-assay CVs, evaluated on
control materials, were 2.0% and 2.4 % for high (68.6 mmol/mol) and low (36.8 mmol/mol) control levels, respectively.
Results in three blood samples with various concentrations of HbA1c (36, 60 and 87 mmol/mol) were not affected by
variation in total hemoglobin concentrations (between 40 to 180 g/L). Only at very low total hemoglobin concentration,
the imprecision was slightly higher (CV 3.1%). The results obtained by capillary electrophoresis (y-method) were well
correlated with those obtained by the HPLC Tosoh G8 (x-method) (y = 0.73 + 0.978x, r=0.998, n=100)
Sensitivity analysis of a sensitivity analysis : We are likely overlooking the impact of distributional assumptions
No full textAlthough uncertainty in input factor distributions is known to affect sensitivity analysis (SA) results, a standard procedure to quantify its impact is not available. We addressed this problem by performing a SA (generating sample of parameter distributions) of a SA (generating samples of parameter values for each generated distribution) of the WARM rice model using the Sobol’ method. The sample of distributions was generated using distributions of jackknife statistics calculated on literature values. This allowed mimicking the differences in distributions that could derive from different selection of literature sources. Despite the very low plasticity of WARM, the ranks of the two most relevant parameters was overturned in 22% of the cases and, in general, differed from what achieved in earlier SAs performed on the same model under similar conditions. SA results were mainly affected by uncertainty in distribution of parameters involved in non-linear effects or interacting with others. The procedure identified parameters whose uncertainty in distribution can alter SA results, i.e., parameters whose distributions could need to be refined
Standardizzazione dell’emoglobina glicata nell’ambito dello studio DAI
No full textThe results obtained from 85 antidiabetic centers enrolled in the DAI study are presented with regard to the external quality assessment scheme for glycohemoglobin. The materials have been prepared by a laboratory of the network of reference laboratories of the International Federation of Clinical Chemistry (IFCC). To each control a Diabetes Control and Complications Trial (DCCT) traceable target value was assigned. The High-Performance Liquid Chromatography (HPLC) methods for glycohemoglobin are used in 75% of the centers, the immunochemical techniques in 21% and less than 5% is using affinity chromatography based methods. The data collected from the laboratories who completed the set of measurements show that 64% of the centers are well aligned to the DCCT system. The reproducibility of the methods varied between 3.7 and 5.8% (as CV, %) and has to be improved
I "microarray" a proteine per una medicina personalizzata
No full textOver the last 10 years, DNA microarrays have achieved a robust analytical performance, enabling their use for analyzing the whole transcriptome or for screening thousands of single-nucleotide polymorphisms in a single experiment. DNA microarrays allow scientists to correlate gene expression signatures with disease progression, to screen for disease-specific mutations, and to treat patients according to their individual genetic profiles; however, the real key is proteins and their manifold functions. It is necessary to achieve a greater understanding of not only protein function and abundance but also their role in the development of diseases. Protein concentrations have been shown to reflect the physiological and pathologic state of an organ, tissue, or cells far more directly than DNA, and proteins can be profiled effectively with protein microarrays, which require only a small amount of sample material. Protein microarrays have become well-established tools in basic and applied research, and the first products have already entered the in vitro diagnostics market. This review focuses on protein microarray applications for biomarker discovery and validation, disease diagnosis, and use within the area of personalized medicine. Protein microarrays have proved to be reliable research tools in screening for a multitude of parameters with only a minimal quantity of sample and have enormous potential in applications for diagnostic and personalized medicine. Copyright original
Sources and performance criteria of uncertainty of reference measurement procedures
No full textObjective: This article wants to focus on the today available Reference Measurement Procedures (RMPs) for the determination of various analytes in Laboratory Medicine and the possible tools to evaluate their performance in the laboratories who are currently using them. Methods: A brief review on the RMPs has been performed by investigating the Joint Committee for Traceability in Laboratory Medicine (JCTLM) database. In order to evaluate their performances, we have checked the organization of three international ring trials, i.e. those regularly performed by the IFCC External Quality assessment scheme for Reference Laboratories in Laboratory Medicine (RELA), by the Center for Disease Control and Prevention (CDC) cholesterol network and by the IFCC Network for HbA1c. Results: Several RMPs are available through the JCTLM database, but the best way to collect information about the RMPs and their uncertainties is to look at the reference measurement service providers (RMS). This part of the database and the background on how to listed in the database is very helpful for the assessment of expanded uncertainty (MU) and performance in general of RMPs. Worldwide, 17 RMS are listed in the database, and for most of the measurands more than one RMS is able to run the relative RMPs, with similar expanded uncertainties. As an example, for a-amylase, 4 SP offer their services with MU between 1.6 and 3.3%. In other cases (such as total cholesterol, the U may span over a broader range, i.e. from 0.02 to 3.6%). With regard to the performance evaluation, the approach is often heterogenous, and it is difficult to compare the performance of laboratories running the same RMP for the same measurand if involved in more than one EQAS. Conclusions: The reference measurement services have been created to help laboratory professionals and manufacturers to implement the correct metrological traceability, and the JCTLM database is the only correct way to retrieve all the necessary important information to this end
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