| RF | radial fiber; radio frequency; receptive field; regurgitant fraction; Reitland-Franklin [unit]; rela... |
|---|---|
| rOEF | regional oxygen extraction fraction |
| RVEF | right ventricular ejection fraction; right ventricular end-flow |
| SF | Sabin-Feldman [test]; safety factor; salt-free; scarlet fever; screen film; seminal fluid; serosal f... |
| SPF | skin protection factor; specific-pathogen free; spectrophotofluorometer; S-phase fraction; split pro... |