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?
**Core Concept**
Infliximab is a monoclonal antibody targeting tumor necrosis factor-alpha (TNF-α), a cytokine involved in the inflammatory process of rheumatoid arthritis. Before initiating treatment with infliximab, it is essential to assess the patient's risk of developing infections, particularly those caused by opportunistic pathogens.
**Why the Correct Answer is Right**
The correct answer is **B. Tuberculosis (TB) screening**. This is because TNF-α plays a crucial role in containing latent TB infection. Inhibiting TNF-α with infliximab can reactivate latent TB, leading to active disease. Therefore, a TB screening test, such as a chest X-ray and/or an interferon-gamma release assay (IGRA), is necessary to identify patients with latent TB before starting infliximab therapy.
**Why Each Wrong Option is Incorrect**
**Option A:** Hepatitis B screening is not the primary concern for patients starting infliximab. While hepatitis B vaccination is recommended for patients receiving TNF-α inhibitors, hepatitis B screening is more relevant for patients on immunosuppressive therapy.
**Option C:** Testing for hepatitis C is not directly related to the initiation of infliximab therapy. However, patients with chronic hepatitis C may be treated with TNF-α inhibitors, and screening for hepatitis C is essential in this context.
**Option D:** Screening for varicella-zoster virus (VZV) is not a standard requirement before starting infliximab. While VZV vaccination is recommended for patients on immunosuppressive therapy, it is not a prerequisite for initiating infliximab.
**Clinical Pearl / High-Yield Fact**
It is essential to note that patients on TNF-α inhibitors, including infliximab, require regular monitoring for signs of infection, particularly those caused by opportunistic pathogens such as TB and histoplasmosis.
**Correct Answer:** B. Tuberculosis (TB) screening.