Systems, devices, and methods of the present application relate to the diagnostic measurement of condition for pressure ulcers. Preferred embodiments utilize pressure measurements at body locations to determine a diagnostic pressure ulcer value. A pressure sensor device generates patient pressure data that is processed by a data processor which utilizes a diagnostic function to determine the diagnostic value that indicates whether corrective action is needed to prevent pressure ulcer formation. One or more sensor devices can be attached to a patient to measure to transmit data for further processing.