Embodiments of the present invention provide antibody functionalized high electron mobility transistor (HEMT) devices for marine or freshwater pathogen sensing. In one embodiment, the marine pathogen can be Perkinsus marinus. A sensing unit can include a wireless transmitter fabricated on the HEMT. The sensing unit allows testing in areas without direct access to electrical outlets and can send the testing results to a central location using the wireless transmitter. According to embodiments, results of testing can be achieved within seconds.