| Parameter | Criteria |
| 1 | Age at onset <40 years |
| 2 | Insidious onset |
| 3 | Improvement with exercise |
| 4 | No improvement with rest |
| 5 | Pain at night (with improvement upon getting up) |
Sensitivity 77.0% and specificity 91.7% if at least four out of five parameters are present. Note that sensitivity and specificity refer to the presence of IBP, not to diagnosis.