| FIF | feedback inhibition factor; fibroblast interferon; forced inspiratory flow; formaldehyde-induced flu... |
|---|---|
| FIF50 | forced inspiratory flow at 50% of forced vital capacity |
| FIO2 | forced inspiratory oxygen; fractional concentration of oxygen in inspired gas |
| FIS | forced inspiratory spirogram; free induction signal |
| FIV | feline immunodeficiency; forced inspiratory volume |