A system is disclosed for the detection of blood flow. The system provides, a portable transceiver unit having a signal generator, a signal comparator, and an audio output whereby a user receives an audio signal indicating differences in Doppler signal, and a Doppler probe coupled to the portable transceiver. The Doppler probe including a piezoelectric crystal disposed at a first end of the Doppler probe; at least one wire transmitting signals between the transceiver unit to the piezoelectric crystal; a rigid or flexible sheath disposed around at least part of the at least one wire and the piezoelectric crystal; and a transceiver unit coupler disposed at a second end of the Doppler probe. The system may also have a quantitative blood flow meter or signal strength meter.