The Medical Service Corps is a staff corps of the United States Navy, consisting of officers engaged in medical support duties. It includes healthcare scientists and researchers, comprising around 60% of its personnel, and healthcare administrators, comprising the remaining 40%. Many of the latter are former enlisted hospital corpsmen, this being the hospital corpsman's route to commissioned status. The Medical Service Corps has around 2,600 serving commissioned officers. Healthcare Sciences are subdivided into the following fields of specialty: