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Concept: Validation

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We aimed to derive and validate a clinical decision rule (CDR) for suspected cardiac chest pain in the emergency department (ED). Incorporating information available at the time of first presentation, this CDR would effectively risk-stratify patients and immediately identify: (A) patients for whom hospitalisation may be safely avoided; and (B) high-risk patients, facilitating judicious use of resources.

Concepts: Myocardial infarction, Hospital, Heart, Validation, Avicenna, Decision theory, Acute coronary syndrome, Chest pain

174

BACKGROUND: Despite considerable global investigation over several decades, the roles of vitamin D in health and disease development remains convoluted. One recognised issue is the difficulty of accurately measuring the active forms of vitamin D. Advances made include some new methods addressing the potential interference by excluding epimers and isobars. However, there is no evidence that epimers are without function. Therefore, the aim of this study was to develop and validate, for the first time, a new assay to simultaneously measure levels of 6 forms of vitamin D along with two epimers. The assay was applied to multilevel certified reference material calibrators and 25 pooled human sera samples obtained from the Vitamin D External Quality Assessment Scheme (DEQAS) to demonstrate its efficiency. RESULTS: The assay is capable of simultaneously measuring 8 vitamin D analogues over the calibration ranges and LODs (in nmol/L) of: 1alpha25(OH)2D2 [0.015-1; 0.01], 1alpha25(OH)2D3 [0.1-100; 0.01], 25OHD3 [0.5-100, 0.025], 3-epi-25OHD3 [0.1-100, 0.05], 25OHD2 [0.5-100, 0.025], 3-epi-25OHD2 [0.1-100, 0.05], vitamin D3 [0.5-100, 0.05] and vitamin D2 [0.5-100, 0.05], using stanozolol-d3 as internal standard. Certified reference material calibrators and external quality control samples (DEQAS) were analysed to meet the standards outlined by National Institute of Standards and Technology (NIST). Validation steps included recovery and both precision and accuracy under inter- and intra-day variation limit of detection, and analysis of each analyte over a linear range. All validation parameters were in line with acceptable Food and Drug Administration (FDA) guidelines and the standards of the National Institute of Standards and Technology (NIST). All eight analogues were quantified with the 25OHD levels being commensurate with DEQAS data. CONCLUSIONS: This report details the application of a new LC-MS/MS based assay for the efficient analysis of eight analogues of vitamin D over a range of samples, which is a significant advance over the existing methods. Simultaneous measure of 8 vitamin D analogues does not compromise the analytical capability of the assay to quantify the commonly used biomarker (25OHD) for vitamin D status. The results demonstrate the feasibility of applying the assay in research and clinical practice that i) excludes misleading measures owing to epimers and isobars and ii) is able to quantify the excluded component to facilitate further in vivo investigation into the roles of ubiquitous epimers.

Concepts: Vitamin D, Mass spectrometry, Measurement, Validation, Analytical chemistry, Standard, Calibration, Certified reference materials

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A small number of nomograms have been previously developed to predict the individual survival of patients who undergo curative resection for gastric cancer. However, all were derived from single high-volume centers. The aim of this study was to develop and validate a nomogram for gastric cancer patients using a multicenter database.

Concepts: Validation, Stomach, Nomogram

148

Chronic kidney disease (CKD) is a major and increasing constituent of disease burdens worldwide. Early identification of patients at increased risk of developing CKD can guide interventions to slow disease progression, initiate timely referral to appropriate kidney care services, and support targeting of care resources. Risk prediction models can extend laboratory-based CKD screening to earlier stages of disease; however, to date, only a few of them have been externally validated or directly compared outside development populations. Our objective was to validate published CKD prediction models applicable in primary care.

Concepts: Chronic kidney disease, Validation

142

The objective of this study was to determine whether kinematic data collected by the Microsoft Kinect 2 (MK2) could be used to quantify postural stability in healthy subjects. Twelve subjects were recruited for the project, and were instructed to perform a sequence of simple postural stability tasks. The movement sequence was performed as subjects were seated on top of a force platform, and the MK2 was positioned in front of them. This sequence of tasks was performed by each subject under three different postural conditions: “both feet on the ground” (1), “One foot off the ground” (2), and “both feet off the ground” (3). We compared force platform and MK2 data to quantify the degree to which the MK2 was returning reliable data across subjects. We then applied a novel machine-learning paradigm to the MK2 data in order to determine the extent to which data from the MK2 could be used to reliably classify different postural conditions. Our initial comparison of force plate and MK2 data showed a strong agreement between the two devices, with strong Pearson correlations between the trunk centroids “Spine_Mid” (0.85 ± 0.06), “Neck” (0.86 ± 0.07) and “Head” (0.87 ± 0.07), and the center of pressure centroid inferred by the force platform. Mean accuracy for the machine learning classifier from MK2 was 97.0%, with a specific classification accuracy breakdown of 90.9%, 100%, and 100% for conditions 1 through 3, respectively. Mean accuracy for the machine learning classifier derived from the force platform data was lower at 84.4%. We conclude that data from the MK2 has sufficient information content to allow us to classify sequences of tasks being performed under different levels of postural stability. Future studies will focus on validating this protocol on large populations of individuals with actual balance impairments in order to create a toolkit that is clinically validated and available to the medical community.

Concepts: Validation, Artificial intelligence, Biomechanics, Pearson product-moment correlation coefficient, Measuring instrument, Noun class, Force platform, Center of mass

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The identification and evaluation of activities capable of dislodging calyceal renal calculi require a patient surrogate or validated functional pyelocalyceal renal model.

Concepts: Validation

31

We previously derived the Ottawa Subarachnoid Hemorrhage Rule to identify subarachnoid hemorrhage (SAH) in patients with acute headache. Our objective was to validate the rule in a new cohort of consecutive patients who visited an emergency department.

Concepts: Hospital, Validation, Subarachnoid hemorrhage, Verification and validation

29

The original Manchester Acute Coronary Syndromes model (MACS) ‘rules in’ and ‘rules out’ acute coronary syndromes (ACS) using high sensitivity cardiac troponin T (hs-cTnT) and heart-type fatty acid binding protein (H-FABP) measured at admission. The latter is not always available. We aimed to refine and validate MACS as Troponin-only Manchester Acute Coronary Syndromes (T-MACS), cutting down the biomarkers to just hs-cTnT.

Concepts: Nutrition, Blood, Myocardial infarction, Validation, Biochemistry, Troponin, Hydrolysis

29

A growing body of evidence is documenting the significant role of cognitive factors in influencing gambling behaviors. Although measures of cognitive biases have been developed, further validation of these scales is needed among non-Western samples. The 21-item Gamblers' Belief Questionnaire was originally developed and validated by Steenbergh et al. (in Psychol. Addict. Behav., 16: 143-149, 2002). The scale then has been widely used in the gambling research of the West. The present study was designed to examine and validate the Chinese version of Gamblers' Belief Questionnaire (GBQ-C) using 258 Chinese participants. Confirmatory factor analyses indicated the 2-factor model provided a good fit to the data as evidenced by various model fit indices (CFI = .91, RMSEA = .08 and SRMR = .05). Additional evidence for the validity of the GBQ-C was provided by significant correlations with other relevant measures (range .40-.75). In sum, the present study provides support for the GBQ-C as a valuable tool for assessing gambling cognitions among Chinese samples.

Concepts: Psychology, Critical thinking, Validation, Cognition, Factor analysis, Cognitive bias, Anecdotal evidence

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The determination of factor VIII (FVIII) potency in FVIII concentrates can be performed using both manual and automated methods. This work aimed to validate the use of the chromogenic kit Coamatic(®) FVIII (Chromogenix) on the automated ACL(®) Elite PRO analyzer for evaluating the potency of FVIII in commercial preparations in pharmaceutical analytical laboratories. After setting the activation and reading times to 2 min and 3 min, respectively, the validation parameters, according to the International Conference on Harmonisation of Technical Requirements for Registration of Pharmaceuticals for Human Use guideline Q2 (R1), were as follows: linearity, expressed by the adjusted model: log (Absorbance) = 1.848 + 0.777∙log (Concentration), with r(2)  = 0.998; accuracy was verified (P-value = 0.6959); and the coefficient of variation for repeatability and intermediate precision was ≤6.5%. The Coamatic(®) FVIII kit method has been adapted to the ACL Elite PRO analyzer with improved performance compared with a manual microplate method.

Concepts: Pharmacology, Validation, Psychometrics, Performance, Pharmaceutical drug, Factor VIII, Verification, Verification and validation