Table 2.

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.