Abstract: The present invention uses an efficient data compression/decompression scheme using a passive data storage media such as a card-based approach for storage of medical data information. The invention operates on existing personal computer hardware in a medical center or doctors' offices, doing away with expensive investments in specialized technologies of central processing hardware. The invention is very economical to implement, at a cost of less than a dollar per card generated for a patient's use. With the advent of inexpensive desktop computing, a number of inventions have been offered to improve medical information storage and retrieval. They include the development of portable medical card technologies such as SmartCards and optical cards which are capable of storing medical information and can be carried by the patient. This card based system provides a methodology for storage and retrieval of medical information from a passive credit-card sized instrument.