THE NUMBER OF ALLIED MEDICAL PERSONNEL HAS INCREASED THREEFOLD IN THE PAST TWO DECADES. FORMERLY, THIS GROUP COMPRISED MAINLY NURSES, MEDICAL OFFICE ASSISTANTS, SOCIAL WORKERS, AND LABORATORY, DIAGNOSTIC, AND TREATMENT TECHNICIANS (INCLUDING TRIAGE PERSONNEL). PHYSICIANS' ASSISTANTS ARE A NEWER CATEGORY OF ALLIED MEDICAL PERSONNEL. THEY VARY GREATLY IN MEDICAL SPECIALTY AREA, LEVEL OF RESPONSIBILITY, AND SPECIFIC TITLE AND INCLUDE NURSE PRACTITIONERS, NURSE MIDWIVES, AND MEDICAL TECHNICAL ASSISTANTS. THIS LAST GROUP WAS DEVELOPED BY THE U.S. BUREAU OF PRISONS TO ASSIST PHYSICIANS BY CONDUCTING SICK CALLS, GIVING EMERGENCY CARE, ACTING AS OPERATING ROOM NURSES, AND GIVING COMPREHENSIVE NURSING CARE IN WARDS. CURRENTLY, 39 STATES HAVE SOME TYPE OF LEGISLATION REGULATING THE USE OF PHYSICIANS' ASSISTANTS.