The Regenstrief Clinical Laboratory System (RCLS) has been operational since 1975 at Wishard Memorial Hospital in Indianapolis, Indiana. The clinician support, use of a true data base management system, and the user interfaces distinguish this system from many commercially available laboratory systems. Physician reports include laboratory, clinical (e.g., physical examination), pharmacy, and radiology data in a single, compact flow sheet. The system can search patient medical records for conditions that may require corrective action and inform physicians of the reasons these actions should be considered. The RCLS data base and its flexible data retrieval capabilities provide a variety of effective technics for monitoring laboratory utilization. The site-specific modifications required to transport this system do not require reprogramming. Important laboratory support features include highly "user friendly" design, multiple specimen numbering sequences, large amounts of free text, reports that can be tailored by non-programmer personnel, CAP accounting statistics, online instrument interfaces, and extensive online instructional facilities.