Soluble antigen fluorescent antibody (SAFA) test is not useful in childhood tuberculosis

The diagnostic value of the soluble antigen fluorescent antibody (SAFA) test in childhood tuberculosis was studied in 117 children in the age group 0-12 years; 79 cases belonged to the study group, 23 children were non-tuberculous controls and 15 were tuberculin-negative healthy controls. The SAFA test was positive in 35 of 44 children with only pulmonary tuberculous lesions (80%) and in 21 of 35 children with other types of tuberculosis (60%). In the 23 non-tuberculous and 15 healthy controls it was positive in 11 cases (48%) and 7 cases (47%), respectively. The sensitivity, specificity and predictivity of the test were found to be 71%, 53% and 72%, respectively. The diagnostic value of the SAFA test was thus found to be low in childhood tuberculosis, especially in disseminated disease and tuberculous meningitis.