This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Communicable Diseases, Subject name: Social & Preventive Medicine
[{'content': 'Which of the following statements about lepromin test is not true? \nSelect and explain. \nA. It is negative in most children in first 6 months of life, B. It is a diagnostic test, C. It is an important aid to classify type of leprosy disease, D. BCG vaccination may convert lepra reaction from negative to positive', 'role': 'user'}, {'content': "Answer: B \nExplanation: Ans. is 'b' i.e. It is a diagnostic test Lepromin test is not a diagnostic test, as it may give positive result in normal subjects and negative results in lepromatous and near-lepromatous cases.Uses of Lepromin testto evaluate the immune status (cell mediated immunity) of leprosy patientsin classifying the diseaseto estimate the prognosis of leprosy patients.Procedure and InferenceThis test is performed by injecting intradermally 0.1 ml of lepromin into the inner aspect of the forearm. Reaction is read at 48 hrs and 21 days.Two types of positive reactions have been described.Early Reaction or Fernandez reactionthis appears as an area of redness and induration at the site of inoculationit develops within 24 to 48 hrs and disappears after 3 to 4 days.the reading is taken at 48 hrs, and if the area of redness is more than 10 mm, the test is considered positive.Late Reaction or Mitsuda reactionthis reaction develops late, becoming apparent in 7-10 days following the infection and reaches peak in 3 or 4 weeks. A nodule develops at the site of inoculation.the reading is taken at 21 days and if the nodule is more than 5 mm in diameter, the reaction is said to be positive.The early reaction is induced by soluble constituents of the leprosy bacilli; and the late reaction by the bacillary component of the antigen.The early positive reaction indicates whether or not a person has been previously sensitized by exposure to an infection by leprosy bacilli. It is thus more superior to late reaction.The early reaction corresponds to the Mantoux reaction in tuberculosis.In the first 6 months of life, most children are lepromin negative; gradually with increasing age more and more persons become positive.BCG vaccination can convert lepra reactions from negative to positive in large no. of individuals.", 'role': 'assistant'}]