| FENa, FENa | fractional excretion of sodium |
|---|---|
| FER | flexion, extension, rotation; fractional esterification rate |
| FFWC | fractional free water clearance |
| FOS | fiberoptic sigmoidoscopy; fractional osteoid surface |
| FPR | false-positive rate; finger peripheral resistance; fluorescence photobleaching recovery; N-formylpep... |