|Discovering additional biomarkers aims to increase sensitivity, but this requires methods for combining information in multiple biomarkers. For two biomarkers, the common OR rule (positive test if either marker positive) increases sensitivity but decreases specificity. Since an additional biomarker provides more information than a single biomarker, it should be possible to increase the sensitivity without sacrificing specificity. Standard statistical methods often increase accuracy with additional biomarkers but at some point, often after few additional biomarkers, accuracy decreases. We will explore this phenomenon, suggest one reason why it occurs, and briefly compare methods for combining multiple biomarkers.