Abstract: Diagnostic techniques are provided to enable the detection of a respiratory condition within a patient's body. The diagnostic techniques compare the acoustic generation and transmission characteristics of the patient's chest and lungs to reference acoustic characteristics and/or predetermined threshold values to determine if an abnormal respiratory condition is present within the patient. The diagnostic techniques process sound waves or vibrations that have interacted with a respiratory condition within a patient and which impinge on the chest wall of the patient. The sound waves or vibrations may be initiated by a speaker that emits sounds waves into the mouth and trachea of the patient or may be indigenous sounds. Alternatively, the sounds waves or vibrations may be initiated using percussive inputs to the chest wall of the patient.