What is the role of Tuberculin test(Mantoux test) in the diagnosis of tuberculosis?
The tuberculin test is very often used in measuring prevalence of infection in epidemiological surveys.But its routine use in diagnosis of tuberculosis in India is discouraged for the following reasons: 1.Because of the high prevalence of infection in adults,the test is likely to be positive in many individuals with infection altough no disease is present 2.Infection by other(even non pathogenic) mycobacteria can result in a positive test,but usually a weakly positive test. On the other if other evidence suggests the diagnosis of tuberculosis,a negative tes does not exclude tuberculosis.False negative tests may be obtained in: 1.Severe malnutrition 2.Diseases which affect T cell dependent immunity viz :HIV infection,or patients receiving corticosteroids.
