Dr. Poretz received his medical degree from the Medical College of Virginia (now Virginia Commonwealth University) where he also completed his internship, residency, and Infectious Diseases fellowship. He is board certified in both internal medicine and the subspecialty of Infectious Diseases. After serving two years as a major in the United States Army Medical Corp, Dr. Poretz was appointed chief of the Infectious Diseases section at Inova Fairfax Hospital in Falls Church, Virginia from 1972 until 2001, and was president of the medical staff from 1985 to 1987. Since that time, he has been in the private practice of Infectious Diseases.

He is a clinical professor of internal medicine at Georgetown University School of Medicine in Washington, DC. Additionally, he has served as a consultant to several insurance and pharmaceutical companies. In 2002, he was appointed to the Anti-Infective Advisory Committee of the FDA. Dr. Poretz is a fellow of both the American College of Physicians and the Infectious Diseases Society of America (IDSA) where he has served on several committees and was elected a councilor. He is presently vice president of the National Foundation for Infectious Diseases and is a member of the American Association for the Advancement of Science, the American Society for Microbiology, the American Medical Association, the Medical Society of Virginia, the Fairfax County Medical Society, the Virginia Infectious Diseases Society, and the Greater Washington Infectious Diseases Society.

Dr. Poretz has published over sixty articles in such scholarly journals as Infectious Diseases in Clinical Practice, International Journal of Antimicrobial Agents, and Clinical Infectious Diseases. He is section editor of "Issues in Clinical Practice" for Infectious Diseases in Clinical Practice. His research interests include clinical studies on AIDS-related infections, new antimicrobials, and outpatient intravenous antibiotic therapy. Dr. Poretz is an invited lecturer and has presented his research findings at medical conferences nationally. He has received the Vicennial Medal from Georgetown University Medical School, a certificate of recognition for outstanding contribution to teaching excellence at Inova Fairfax Hospital, and he was enshrined in the Leon G. Smith Infectious Diseases Institute Hall of Fame at St. Michael's Medical Center in Newark, New Jersey. He is consistently voted by his peers as one of the outstanding Infectious Diseases physicians as published in The Washingtonian Magazine and The Best Doctors in America. He was awarded the "Clinician of the Year" award in 2004 by the Infectious Diseases Society of America.