| Abbreviation | Definition |
|---|---|
| NIP | No infection present |
| NIP | No Inflammation Present |
| NIPS | Neural Information Processing System |
| NIPS | Non Invasive Programmed Stimulation |
| NIR | Natural Increase Rate |
| NIR | New Intravascular Rigid |
| NIRS | Non- Invasive Research System |
| NIS | Sodium-Iodide Symporter |
| NIT | Nitrate |
| NIT | noninvasive testing |
| NITR | Nitrite |
| NIV | Non-Invasive Ventilation |
| NK | natural killer cell |
| NK | NeuroKinin |
| NKA | No Known Allergies |
| NKD | No known disease |
| NKDA | Non-Ketotic Diabetic Acidosis |
| NKH | Non-Ketotic Hyperglycinemia |
| NL | Normal |
| NL | Normal Limits |