This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Immunology, Subject name: Microbiology
Skin test useful in Hydatid disease is? 
Select and explain. 
A. Casoni's test, B. Schick test, C. Patch test, D. Dick s test
A: Casoni's test
Answer: A: Casoni's test 
Explanation: ANSWER: (A) Casoni's testREF: Paniker's 6th ed p. 149The Casoni test is a skin test used in the diagnosis of hydatid disease. The test involves the intradermal injection of 0.5 ml of sterilised fluid from hydatid cysts. A wheal response occurring at the injection site within 20 minutes is considered positive. The test is positive in about 90% of cases of hydatid disease affecting the liver, but positive in less than 50% of patients with hydatid disease elsewhere in the body; false positive results are also common. Consequently, serological tests are nowr generally used.Dick's test: Scarlet fever Schick's test: Diphtheria