| TRR | total respiratory resistance |
|---|---|
| TSR | theophylline sustained release; thyroid to serum ratio; total systemic resistance |
| TSVR | total systemic vascular resistance |
| TTR | transthoracic resistance; transthyretin; triceps tendon reflex |
| TVR | tonic vibratory reflex; total vascular resistance; tricuspid valve replacement |