This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Other topics and Adverse effects, Subject name: Pharmacology
Mrs Reeta Wardhan, A 50-year-old female with rheumatoid ahritis is being considered for infliximab therapy. Which of the following tests should be performed before beginning treatment? 
Select and explain. 
A. Liver function tests, B. PPD skin test, C. Pulmonary function tests, D. Visual examination
B: PPD skin test
Answer: B: PPD skin test 
Explanation: (Ref: Katzung 11/e p633) Infliximab is a monoclona antibody against TNF-a. It is commonly used to treat moderate to severe rheumatoid ahritis paicularly in patients who have failed methotrexate therapy. TNF-a inhibitors can cause serious adverse effects, including reactivation of latent tuberculosis. All patents being considered for TNF-a inhibitor therapy should have a baseline PPD skin test to screen for latent tuberculosis.