Figure 4. Afirma gene expression classifier clinical validation negative predictive value versus hypothetical “operative negative predictive value”. These phenomena co-exist, rather contradict each other. Outside of a properly designed clinical validation study (Figure 5), the “operative negative predictive value” from clinical experience studies creates significant confusion while offering little clinical value *Alexander et al. (4), †Afirma gene expression classifier benign cases referred to surgery due to ultrasound features, ultrasound changes over time, nodule growth, etc., GEC: Gene expression classifier.
