Devices and methods for improving the sensitivity and specificity of heart failure (HF) detection are described. The devices and methods can detect a HF status such as using physiological sensor data and external biomarker assays. An apparatus can comprise ambulatory physiological sensors that can provide a first HF status indicator and a second HF status indicator to a user. An external biomarker sensor can provide an amount of a biomarker present, such as an assay for B-type natriuretic peptide (BNP), which provides information about HF status. A processor circuit can switch from a first HF detection mode to a second detection mode such as in response to the information from the biomarker sensor. The first detection mode can detect HF status using the first HF status indicator, and the second detection mode can detect HF status using the second HF status indicator. The second detection mode can have a higher specificity than the first detection mode.
