One month after starting infliximab, which laboratory test should be checked?

• A. Renal function test
• B. Lipid panel
• C. CBC
• D. Thyroid function

Answer: (C)

Starting infliximab, a TNF-alpha inhibitor, carries a risk of impaired immune function and blood cell abnormalities. The most useful early safety check is a complete blood count because it directly reveals hematologic issues such as neutropenia, anemia, or thrombocytopenia, which can develop after initiation and raise infection risk. Checking a CBC about a month after starting therapy helps catch these potential problems early and guides whether to continue, adjust, or pause treatment.

Renal function, lipid panel, and thyroid function aren’t specifically targeted by this class of medication and are less likely to reflect early adverse effects from infliximab. Baseline screening for latent tuberculosis and hepatitis B is important before starting therapy, but that’s a pre-treatment step rather than the one-month follow-up lab.