Power management circuitry of a portable electronic biosensor implements conditional power management logic to control biosensor power usage and to discriminate between intended use and nonuse of the biosensor by a clinician. The biosensor is configured to sense a property of the human body, such as a manifestation of acoustic energy produced by matter of biological origin or an action potential of the human body. An output signal is produced that is representative of the sensed property. A sensor of the biosensor produces a signal having a plurality of sensor signal features that are received by a detector of the power management circuitry. The power management circuitry or a processor of the biosensor discriminates between intended use and nonuse of the biosensor by the clinician using the sensor signal features. Power supplied to biosensor components is controlled based on the sensor signal features.