Clinical management changes within 6 months of therapeutic drug monitoring (TDM) tests
| Number of TDM measurements | 672 |
| Number of patients | 238 |
| IFX trough level (μg/ml) | 3.4 (5.4) |
| Positive antibodies, n (%) | 118 (17.6) |
| Undetectable levels, n (%) | 154 (22.9) |
| TDM indication n (%) | |
| Primary non-response | 3 (0.4) |
| Secondary loss of response | 180 (26.8) |
| Reaction to IFX | 9 (1.3) |
| Routine testing | 469 (69.8) |
| Consideration of de-escalation | 11 (1.6) |
| Post TDM management n (%) | |
| Dose escalation | 58 (8.6) |
| Switch to different anti-TNF | 40 (6.0) |
| Switch to non anti-TNF biologic | 12 (1.8) |
| Add thiopurine | 10 (1.5) |
| Stop biologics | 17 (2.5) |
| Treatment de-escalation | 9 (1.3) |
| No action | 526 (78.3) |
| Remission at 6 months | 411 (61.3) |
All values represent median (IQR) unless otherwise indicated. Time and duration is expressed in months.