A virtual medical instrument (VMI) system comprises data storage for storing input diagnostic test protocols for two or more of EEG, EKG, EMG/NCV, PFT, CMG, EP, ENG, visual acuity, visual field, limb dynometric and audiogram testing. The VMI system includes a universal interface having a number of electrical contacts and sets of electrical conduits associated with the different stored diagnostic test protocols. A selector enables a system user to select any one of the stored diagnostic test protocols for conducting on a patient. The system is constructed to enable the selected diagnostic test protocol to be performed on a patient after the corresponding set of electrical conduits are connected to the universal interface contacts and to the patient. Further included is an electrical signal generator connected to the universal interface for providing electrical signals to the patent if such electric signals are required by the selected test protocol. Electrical signals are received by the system through the electrical conduits connected to the universal interface from a patient and an output corresponding to the received electrical signals is provided, the output including one or more of strip chart printer, conventional printer, modem, computer diskette, audio recorder and video recorder.