| A | B |
|---|
| OP | outpatient |
| OPD, OPC | outpatient department or clinic |
| OR | operating room |
| OSHA | Occupational Safety and Health Administration |
| OTC | over the counter |
| OU | each eye |
| OV | office visit |
| P | pulse |
| PA | physician's assistant |
| PAC | premature atrial contraction |
| PCC | poison control center |
| PCP | patient care plan |
| PDR | Physician's Desk Reference |
| PE | physical examination, pulmonary edema |
| PET | positron emission tomography |
| PI | present illness |
| PID | pelvic inflammatory disease |
| PKU | phenylketonuria |
| PM, pm | after noon |
| PMC | postmortem (after death) care |
| opp | opposite |
| Ord | orderly |
| Orth | orthopedics |
| os | mouth |
| OS | left eye, occular sinistra |
| OT | occupational therapy / therapist |
| oz | ounce |
| p | after |
| PAP | Papanicolaou test (smear) |
| para | number of pregnancies |
| Path | pathology |
| Pb | lead |
| PBI | protein bound iodine |
| pc | after meals |
| PCA | patient-controlled analgesia |
| PCT | patient / personal care technician |
| Peds | pediatrics |
| per | by, through |
| pH | measure of acidity / alkalinity |
| Pharm | pharmacy |
