A diagnostic device in an electrical interferential treatment regime applies different pulse frequencies in one selection of electrode placement and determines the change of blood flow in response to the change in pulse frequency in an attempt to determine an optimum or workable set of parameters. The device includes electronic storage to record a series of tests and their results and a communication link. The communication link enables a professional caregiver to determine whether the parameter determinations, made at a location remote from the professional's office, such as at the residence of the patient, were conducted and were conducted correctly. The communication link also enables the professional to determine whether the treatments were conducted and conducted correctly.