Task: Translation
Input (Spanish): Ante un paciente con enfermedad de Crohn que va a comenzar tratamiento con terapia biológica antiTNF (anticuerpos anti factor de necrosis tumoral alfa), ¿cuál de las siguientes pruebas diagnósticas no es necesaria antes de iniciar dicha terapia?
Output (English): In the presence of a patient with Crohn's disease who is going to start treatment with biological anti-TNF therapy (antibodies against tumor necrosis factor alpha), which of the following diagnostic tests is not necessary before initiating such therapy?