It is a diagnostic test Repeat from May 07 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 test 1)to evaluate the immune status (cell mediated immunity) of leprosy patients 2)in classifying the disease 3 )to estimate the prognosis of leprosy patients. Procedure and Inference This 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. a)Early Reaction or Fernandez reaction - this appears as an area of redness and induration at the site of inoculation - it 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. b)Late Reaction or Mitsuda reaction - this 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 conve lepra reactions ,from negative to positive in large no. of individuals