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What is Frei's test is used for the diagnosis of? and explain in detail?
Frei's 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 & Paniker's ed- 8th pg 420.