Abstract: Sleep apnea screening and/or detection apparatus for use by a patient breathing through the nose and/or mouth and producing an air flow into and out of the lungs of the patient and creating audible sounds. It is comprised of a first microphone positioned in the vicinity of the patient's nose and mouth and out of contact therewith to pick up audible sounds created by breathing of the patient and providing a first electrical analog signal. A second microphone is provided which is positioned near the patient for picking up ambient noise in the vicinity of the patient and providing a second electrical analog signal, an active noise controller is provided for combining the first and second electrical analog signals to provide a third electrical signal for generating a fourth electrical signal providing a waveform which is closely correlated with the air flow of the patient.