Please use drug levels as a guide. Infliximab Interpretation: Therapeutic drug levels: >2 µg/mL Intermediate drug levels: 1.0 – 2.0 µg/mL Subtherapeutic drug levels: < 1.0 µg/mL Test interpretation requires full clinical information: drug dosage/frequency, previous exposure to other biologics, time of sampling, duration of therapy and clinical assessment.