| ROI | reactive oxygen intermediate; region of interest; right occipitolateral [fetal position] |
|---|---|
| ROS | reactive oxygen species; review of systems; rod outer segment |
| RP | radial pulse; radiopharmaceutical; rapid processing [of film]; Raynaud phenomenon; reactive protein;... |
| RPC | reactive perforating collagenosis; relapsing polychondritis; relative proliferative capacity |
| SARA | sexually acquired reactive arthritis; Superfund Amendments and Reauthorization |