| RDI | recommended daily intake; respiratory disturbance index; rupture-delivery interval |
|---|---|
| RFI | radiofrequency interference; recurrence-free interval; renal failure index |
| SDI | standard deviation interval; survey diagnostic instrument |
| STI | Scientific and Technical Information; serum trypsin inhibitor; soybean trypsin inhibitor; systolic t... |
| TID | time interval difference [imaging]; titrated initial dose |