| RRpm | respiratory rate per minute |
|---|---|
| RRT | random response technique; Registered Respiratory Therapist; relative retention time |
| RRU | respiratory resistance unit |
| RS | radioscaphoid; random sample; rating schedule; Raynaud syndrome; recipient's serum; rectal sinus; re... |
| RSV | respiratory syncytial virus; right subclavian vein; Rous sarcoma virus |