Abstract: A real-time biological data processing PC card is lightweight, cost effective, and portable. The real-time biological data processing PC card is capable of converting a host personal computer system into a powerful diagnostic instrument. Each real-time biological data processing PC card is adapted to input and process biological data from one or more biological data sensors, and is interchangeable with other real-time biological data processing PC cards. A practitioner having three different real-time biological data processing PC cards, for example, each one corresponding to a different biological data collection device, effectively carries three full-sized, powerful diagnostic instruments. The full resources of a host personal computer can be utilized and converted into a powerful diagnostic instrument, for each biological data collection device, by the insertion of one of the real-time biological data processing PC cards.