This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: G.I.T, Subject name: Anatomy
[{'content': 'Diagnosis of Hydatid disease is by - \nSelect and explain. \nA. Biopsy, B. X-ray, C. Casoni test, D. Serum examination', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Serological tests are the most sensitive and specific tests; includes Immunoblast test, arcs test, ELISA and indirect hemagglutination tests. "The immunoblast test, where available, is the test of choice." - CMDT, 2005, p 1463. Casoni\'s test - Intradennal injection of 0.2 ml of fresh sterile hydatid fluid produces a wheal of 5 cm in diameter within half an hour in pts with hydatid disease. It has been abandoned because of poor specificity. Ref : CMDT, 2005, p 1462, 1465', 'role': 'assistant'}]