| ETR | effective thyroxine ratio; endothelin receptor |
|---|---|
| ETT | endotracheal tube; epinephrine tolerance test; exercise tolerance test; exercise treadmill test; ext... |
| L-T4 | L-thyroxine |
| PBT4 | protein-bound thyroxine |
| PTL | peritoneal telencephalic leukoencephalomyopathy; pharyngotracheal lumen; plasma thyroxine level post... |