| IFR | infrared; inspiratory flow rate |
|---|---|
| ILS | idiopathic leucine sensitivity; idiopathic lymphadenopathy syndrome; increase in life span; infrared... |
| IR | drop of voltage across a resistor produced by a current; ileal resection; immune response; immunizat... |
| IRED | infrared light-emitting diode |
| IR-LED | infrared light emitting diode |