Biologics and thiopurines are standard therapies in the management of Crohn’s disease (CD) and ulcerative colitis (UC). Reactive therapeutic drug concentration monitoring (TDM) provides insights into the mechanism of loss of response and allows effective and cost-efficient methods of adjusting dose or switching to a different medication. This study aimed to compare practice patterns of reactive TDM among inflammatory bowel disease (IBD) dedicated gastroenterologists (GIs) in tertiary academic center versus general GIs in the community.