Summary The reference interval for a biochemical analyte is usually an interval of values bounded by the reference limit values at certain designated percentiles [1].  As always when choosing a cut-off, the value will determine the trade-off between clinical sensitivity and specificity. When a low cut-off is chosen,...

This article demonstrates that adding a lot of patients without disease and with low test results to a study may improve the ROC curve significantly without any improvement in sensitivity or in positive predictive value of the parameter evaluated. The precision-recall curves are not impacted by the addition of...

When a new D-dimer method is evaluated, it’s typically compared to an established D-dimer method using both an analytical and a clinical comparison. Analytical comparisons should be discouraged, as they do not give any useful information about the potential clinical usability of the assay. D-dimer assay comparisons...

Clinical sensitivity, clinical specificity and predictive values are frequently used as performance measure for a biochemistry assay. When D-dimer assay performance is presented, emphasis is often on the negative predictive value (NPV). However, predictive values are greatly influenced by the prevalence of the...

D-dimer testing can combined with assessment of pretest probability be used to rule out VTE in patients with a sufficiently low pretest probability of VTE. Patients with a negative D-dimer result can be ruled out, while patients with a positive D-dimer result need to have imaging performed for confirmatory diagnosis. ...

The use of natriuretic peptides like B-type natriuretic peptide (BNP) and N-terminal proBNP (NT-proBNP) has increased during the last decade and so has the medical evidence of their utility. This article highlights natriuretic peptide synthesis and release. Based on essential clinical trials the article gives medical...

Clinical biomarker studies seldom follow recommendations for the evaluation of new biomarkers. Therefore it is important to assess any published clinical value of a biomarker or comparison of two or more biomarkers and see whether or not the published study applies to your situation. If the published study does not...

Various guidelines and recommendations are available for the use of natriuretic peptides in the diagnosis of heart failure. As it is known that old age may lead to higher natriuretic peptide values in the absence of heart failure, it is relevant to decide whether to use age-dependent reference intervals for clinical...

ROC curves are frequently used to show in a graphical way the connection/trade-off between clinical sensitivity and specificity for every possible cut-off for a test or a combination of tests. In addition the area under the ROC curve gives an idea about the benefit of using the test(s) in question.  ROC curves are...

When a new D-dimer method is to be implemented either as a substitute for a currently used D-dimer assay or as a supplement, maybe as a point-of-care assay, it is necessary to do a clinical comparison of the "old" assay versus the "new" assay. The major pitfalls in D-dimer comparisons are addressed in this paper.   ...