BACKGROUND There has been considerable debate regarding the impact of assay imprecision on the performance of cardiac biomarkers for diagnosis of acute coronary syndromes (ACS) and risk stratification for future adverse cardiac events. METHODS Using existing data from 2 published clinical trials, we used a resampling method to statistically introduce 5%, 10%, and 20% imprecision to results fo...

BACKGROUND Syndromic surveillance systems can potentially be used to detect a bioterrorist attack earlier than traditional surveillance, by virtue of their near real-time analysis of relevant data. Receiver operator characteristic (ROC) curve analysis using the area under the curve (AUC) as a comparison metric has been recommended as a practical evaluation tool for syndromic surveillance system...

Classification accuracy is the ability of a marker or diagnostic test to discriminate between two groups of individuals, cases and controls, and is commonly summarized using the receiver operating characteristic (ROC) curve. In studies of classification accuracy, there are often covariates that should be incorporated into the ROC analysis. We describe three different ways of using covariate inf...

BACKGROUND ROC (receiver operating characteristic) curve analysis is well established for assessing how well a marker is capable of discriminating between individuals who experience disease onset and individuals who do not. The classical (standard) approach of ROC curve analysis considers event (disease) status and marker value for an individual as fixed over time, however in practice, both the...

We develop a permutation test for assessing a difference in the areas under the curve (AUCs) in a paired setting where both modalities are given to each diseased and nondiseased subject. We propose that permutations be made between subjects specifically by shuffling the diseased/nondiseased labels of the subjects within each modality. As these permutations are made within modality, the permutat...

In a common ROC study design, several readers are asked to rate diagnostics of the same cases processed under different modalities. We describe a Bayesian hierarchical model that facilitates the analysis of this study design by explicitly modelling the three sources of variation inherent to it. In so doing, we achieve substantial reductions in the posterior uncertainty associated with estimates...

PURPOSE Basophil activation occurs both in patients with immediate hypersensitivity reactions to anti-inflammatory drugs and in healthy controls in a dose-dependent manner. Our aims were to define the optimal basophil activation test (BAT) concentration and the threshold for BAT positivity for dipyrone. METHODS From 45 patients with a positive history of an immediate hypersensitivity reaction...

background: the relationships between adiponectin and clinical outcomes in hemodialysis (hd) patients remain highly controversial. meanwhile, the association between adiponectin and the peripheral artery disease (pad) has not been well studied in hd patients without diabetic mellitus. materials and methods: the ankle-brachial index was measured in hd patients. adiponectin levels in 105 hd patie...