Bayesian detection of abnormal values in longitudinal biomarkers with an application to T/E ratio.

Details

Serval ID
serval:BIB_757AAE3745DF
Type
Article: article from journal or magazin.
Collection
Publications
Institution
Title
Bayesian detection of abnormal values in longitudinal biomarkers with an application to T/E ratio.
Journal
Biostatistics
Author(s)
Sottas P.E., Baume N., Saudan C., Schweizer C., Kamber M., Saugy M.
ISSN
1465-4644
Publication state
Published
Issued date
2007
Peer-reviewed
Oui
Volume
8
Number
2
Pages
285-296
Language
english
Abstract
We developed a test that compares sequential measurements of a biomarker against previous readings performed on the same individual. A probability mass function expresses prior information on interindividual variations of intraindividual parameters. Then, the model progressively integrates new readings to more accurately quantify the characteristics of the individual. This Bayesian framework generalizes the two main approaches currently used in forensic toxicology for the detection of abnormal values of a biomarker. The specificity is independent of the number n of previous test results, with a model that gradually evolves from population-derived limits when n = 0 to individual-based cutoff thresholds when n is large. We applied this model to detect abnormal values in an athlete's steroid profile characterized by the testosterone over epitestosterone (T/E) marker. A cross-validation procedure was used for the estimation of prior densities as well as model validation. The heightened sensitivity/specificity relation obtained on a large data set shows that longitudinal monitoring of an athlete's steroid profile may be used efficiently to detect the abuse of testosterone and its precursors in sports. Mild assumptions make the model interesting for other areas of forensic toxicology.
Keywords
Bayes Theorem, Biological Markers, Data Interpretation, Statistical, Doping in Sports, Epitestosterone, Humans, Longitudinal Studies, Male, Models, Statistical, Sensitivity and Specificity, Testosterone
Pubmed
Web of science
Open Access
Yes
Create date
16/05/2008 16:25
Last modification date
20/08/2019 14:32
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