In two weeks, McLean internist Dr. David J. Jones will be taking a giant occupational leap. "As of April 1, I will no longer be accepting medical insurance," he said. "That's it." Jones is one of a growing number of doctors who are becoming increasingly frustrated with what they say is an inefficient primary care health system, and who are moving away from the traditional health care model into what is called "concierge medicine." Also known as "boutique medicine", "retainer-based medicine" or "innovative medical practice design," concierge medicine physicians charge their patients a one-time annual membership fee which is paid out-of-pocket instead of billing insurance companies for individual visits. Currently, the annual fee for patients in Jones' Principal Medical Group is $2,000 for an individual and $3,000 for a couple.