Alarm signs and symptoms
| Age over 50 |
| Gastrointestinal bleeding |
| Anemia |
| Fever |
| Night sweats |
| Unintentional weight loss |
| Family history of organic gastrointestinal disease |
| Other symptoms that should alert provider to consider another diagnosis |
| Nocturnal symptoms |
| Symptoms that persist when fasting |
| Low fecal osmotic gap (fecal osmotic gap = 290 mOsm/kg) – 2 × (stool Na + stool K); a low gap (< 50 mOsm/kg) suggests a secretory cause of diarrhea such as microscopic colitis. Patients with IBS would be expected to have a normal gap. |