This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Dental
[{'content': 'Patch test is read after – \nSelect and explain. \nA. 2 hours, B. 2 days, C. 2 weeks, D. 2 months', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Patch test \n\nPatch test is done in cases of contact dermatitis to establish the etiological agent.\nThis is a simple test involves application of suspected allergen as a patch, usually over upper back.\nThe patch is removed after 48-72 hours and the reading is done and the skin is examined for any signs of dermatitis (erythema, edema and vesicle formation).\nYou should also remember that reading should be taken after 20 minutes to 1 hour after moval of patch.\nSo, two different question can be framed :-\n\n1.Patch test is read after → 2-3 days\n2.In Patch test, reading is done after removal of patch → 30 minutes to 1 hour.', 'role': 'assistant'}]