About Our Doctors

All our physicians are Board Certified and each average over 20 years of clinical practice experience. They regularly practice at Medical Center locations and have years of experience serving the needs of employees and employers.

Mark Ahearn, M.D., FACEP, National Medical Director

Dr. Mark Ahearn serves as National Medical Director for Medicine At Work. He received his MD degree from Tufts University School of Medicine and completed an emergency medicine residency at University of California Los Angeles. He has been a board-certified specialist in emergency medicine for more than 20 years.

Representative Doctor Team Members

Darrell Calderon, MD FACEP

Dr. Calderon is board-certified and has been practicing Medicine since 2000. Along with his service to Medicine At Work, he is a Chief Medical Officer and Director of the Emergency Department of First Texas Hospital.

Barry Diner, MD FACEP

Dr. Diner is board-certified and completed a residency in Emergency Medicine at The Brooklyn Hospital Center, Weill Medical College of Cornell Medical School and was appointed chief resident in his final year. After his move to Houston in 2005, he joined the staff at St. Luke’s Episcopal Hospital.

Jerry Jones, MD FACEP

Dr. Jones began working in emergency departments before the establishment of Emergency Medicine as a specialty, but was allowed to take the examination of the American Board of Emergency Medicine and became board-certified in Emergency Medicine.

Mark Mehaffey, MD FACEP

Dr. Mehaffey is a board certified physician seeing patients in the Texas Medical Center, Houston and has also been the medical director for several Emergency Medical Services companies. He is presently is an Assistant Professor at Baylor College of Medicine.