| OI | obturator internus; occasional insomnia; opportunistic infection; opsonic index; orgasmic impairment... |
|---|---|
| OPSI | overwhelming postsplenectomy infection |
| PI | first meiotic prophase; isoelectric point; pacing impulse; package insert; pancreatic insufficiency;... |
| PNI | peripheral nerve injury; postnatal infection; prognostic nutritional index |
| PTI | pancreatic trypsin inhibitor; persistent tolerant infection; Pictorial Test of Intelligence; placent... |