[R] Sensitivy / Specificity and nulls

[Brecht Devleesschauwer]

Maybe you want to check out the prevalence package 
(http://cran.r-project.org/web/packages/prevalence/index.html), and its 
development version on GitHub (https://github.com/brechtdv/prevalence/). 
When you have two tests, and neither can be considered to be a 'gold 
standard' (ie, SE & SP = 100%), Bayesian latent class approaches can 
help you to estimate true prevalence, sensitivity and specificity.

Brecht


> Good Day All,
>
> I am working with a diagnostic test and comparing the new test to an old
> test.  Normally I would be able to calculate sensitivity and specificity
> quite easily.
>
> However, the 'gold standard' that I am comparing my new diagnostic 
> with is
> really 'gold-plated' in that sometimes the 'gold standard' fails 
> completely
> and I have no data from the 'gold standard' but I might have data from 
> the
> diagnostic test.  Of course sometimes my new diagnostic fails but I have
> data from my 'gold standard'
>
> To me this really starts moving towards classification but I cannot 
> seem to
> find the appropriate calculations.
>
> Can someone point me to some web resources to determine the appropriate
> method to be able to deal with the NULLs ?  Resources within the medical
> realm would be better (because the rest of the folks would understand 
> them
> better) but not required. 


-- 
Devleesschauwer Brecht
Doctoral Researcher, MVSc DVM
Department of Virology, Parasitology and Immunology
Faculty of Veterinary Medicine
Ghent University
Salisburylaan 133
9820 Merelbeke
Belgium

Telephone: +32 9 264 7328
Mobile (Belgium): +32 476 365743
Mobile (Nepal): +977 9842 223323
E-mail: brecht.devleesschauwer at ugent.be

http://users.ugent.be/~bdvleess/