central sterile technician is a technician cleaning all the surgical materials and sterilizing use for surgery and materials needed for surgery.
i dont know what central service is..assuming it may be clerical work rather than medical.
all i can say is if "central service" is considered part of the medical field then you may be out of luck workng as such
u might wanna call the hospital and check for yourself
good luck
i dont know what central service is, you could ask in hep b , section, or ask the hospital, do you need to tell them would they be at risk