It's definitely an interesting dilemma. When it comes to the medical detachment, I can find no information on the members having any kind of white uniform and it would seem that they wore was pretty much what other members of the unit wore. Here's an informative page about WW2 Hospitals and medical personnel:
The jackets that they wear seem more like lab or work coats and they are not wearing ties as all others are. The trousers seem to be white (although that could be from over exposure due to the white shirts) and the headgear seems to be the same as the other soldiers. It seems as though they are wearing some kind of work uniform so could this be a KP uniform or maybe an Orderly uniform for a hospital? Questions, questions...
Gary
Oct 1969 while in boot camp we did a week of mess duty in the chow hall before going to the rifle range, I was a server on the chow line, I wore for that week a white jacket and white trousers so I think these men were on k p or mess duty. if the army wore white while on that duty at that time. Of course if so I wonder why they didn't change uniform's for the photo Ralph