| SIMV | synchronized intermittent mandatory ventilation; synchronized intermittent mechanical ventilation |
|---|---|
| SIN | salpingitis isthmica nodosa |
| SIO | sacroiliac orthosis |
| SIOP | International Society of Pediatric Oncology |
| SIP | Sickness Impact Profile; slow inhibitory potential; surface inductive plethysmography |
| sIPTH | serum immunoreactive parathyroid hormone |
| SIQ | Symptom Interpretation Questionnaire |
| SIQR | semi-interquartile range |
| SIR | single isomorphous replacement; specific immune release; standardized incidence ratio; syndrome of immediate reactivities |
| SIRA | Scientific Instrument Research Association |