Browse Medical Abbreviations

O oral; other; Oxygen (element)
o other
O&E observation and examination
O&P ova and parasites
O-A occipital-atlas
o.d. once daily (omni die)
O.D. right eye (oculus dexter)
o.h. every hour (omni hora)
o.m. every morning (omni mane)
o.n. every night (omni nocte)
O.S. left eye
O/E on examination
O/R oral, rectal
O2 oxygen
O2Sat Oxygen saturation (percent)
o: objective
OA occiput anterior; osteoarthritis; osteoarthrosis
OAE oto acoustic emissions
OB obstetrics or obstetrical
OB+ occult blood positive
OB-Gyn obstetrics and gynecology
OB/GYN obstetrics/gynecology
OBRA omnibus budget reconciliation act
OBS organic brain syndrome
OBS/OBD organic brain syndrome/organic brain disorder
obsd observed
obst obstruct, obstruction
OBT over-bed table
OBUS obstetrical ultrasound
OC obstetrical conjugate; oral contraceptive; osteocalcin
occ occasional
OCD obsessive compulsive disorder
OCG oral cholecystogram
OCL orthopedic cast for limb
OCP oral contraceptive pills
OCR ossicular chain reconstruction
OCT oxytocin challenge test
OD right eye (oculus dexter); overdose; optical density (equivalent to absorbance)
ODT orally disintegrating tablet
OE otitis externa
OFC occipital-frontal circumference
OFTT organic failure to thrive
OG orogastric
OGT oral glucose tolerance (test)
OGTT oral glucose tolerance test
OI opportunistic infection
oint ointment
ol. oil
OM otitis media
OMB operational management board
OME otitis media with effusion
OMH office for migrant health
omn. hor. every hour
omn. noct. every night
OmPC outer membrane porin c
ONS oncology nursing society
OOA offices on aging
OOB out of breath; out of bed
OOR out of room
OOT out of town
OP occiput posterior; operative; outpatient
OPA outpatient with anesthesia
OPD outpatient department
OPER outpatient with extended recovery
OPG oculoplethysmography
Oph(th) ophthalmology, ophthalmoscope
OPHEP Office of Public Health Emergency Preparedness (HHS)
OPHS office of public health and science
OPMS oropharyngeal motility study
opp opposite
OPROC outpatient procedure
opt optical; optimal
OPT outpatient
OPV oral polio vaccine
OR operating room
org organization
ORIF open reduction and internal fixation
ORM operational risk management
ORR objective response rate
ORS oral rehydration solution
Ortho orthopedics
Os Osmium (element)
os mouth; bone
OS left eye (oculus sinister)
OSA obstructive sleep apnea
OSD over bed side drainage
OSHA Occupational Safety and Health Administration
OSHC (OC) Office of Science and Health Coordination (OC)
OSR open septo-rhinoplasty
osteo osteo myelitis
OT occupational therapy; occupational therapist
OTC over the counter
OTFC oral transmucosal fentanyl citrate
oto otoscope
OTR occupational therapist, registered
OU both eyes (oculi unitas); each eye; Orthodox Union
OV office visit
oz ounce