High Negative Predictive Value, Low Prevalence, and Spectrum Effect: Caution in the Interpretation

Nonalcoholic fatty liver disease (NAFLD) is an increasingly common clinical problem found in the primary care setting. The typical scenario includes a patient in whom a mild elevation of transaminases leads to an imaging study reporting a bright liver “compatible with fatty liver.” This finding opens a Pandora’s box of multiple tests and imaging, and sometimes the need for liver biopsy with associated physical, emotional, and financial harms....