<prompt> Freis test is used for the diagnosis of?Lymphogranuloma venereumTuberculoid leprosyHistoplasmosisTuberculosis  <response>: Freis Test: It is the intradermal skin test used for the diagnosis of Lymphogranuloma venereum. A heat inactivated LGV 0.1ml grown in yolk sac of embryonated egg is injected intradermally on the forearm and a material prepared from non infected yolk sac on other forearm control. The test is read after 48-72 hrs. An inflamatory nodule appears at the test site in 2 days reaching a maximum in 4-5 days. The skin test becomes positive 2-6 weeks after infection and remains positive for several years. Must know: Lepromin test is used for the diagnosis of Tuberculoid leprosy. Histoplasmin is used for the diagnosis of Histoplasmosis. Mantoux test is used for the diagnosis of TB. Ref: Ananthanarayanan Panikers ed- 8th pg 420. 