| FEE | forced equilibrating expiration |
|---|---|
| FI | fasciculus intrafascicularis; fever caused by infection; fibrinogen; fixed interval; flame ionizatio... |
| FIO2 | forced inspiratory oxygen; fractional concentration of oxygen in inspired gas |
| FIS | forced inspiratory spirogram; free induction signal |
| FIV | feline immunodeficiency; forced inspiratory volume |