Assessing disease activity in Crohn's disease ‐ are we there yet?

&NA; Many attempts have been made over recent years to assess accurately disease activity in Crohn's disease. We review some of these attempts, giving particular emphasis to the combination of serum levels of proinflammatory cytokines (interleukin‐6, tumour necrosis factor a, recombinant interleukin‐2 and acid &agr;‐1‐glycoprotein).