Evaluation T-SPOT TB test in diagnosis of tuberculosis

Tuberculosis (TB) is a chronic infection disease which more than 50% of untreated patients will die during the period of five years after diagnosis. The main goal in TB program is early diagnosis and treatment. Some biochemical tests such as T-SPOT serologic test could be useful for the rapid diagnosis of tuberculosis. We conducted a cross-sectional study in 60 patients suspected TB which 30 patients were sputum positive and the remainders were sputum negative for acid fast bacilli. After entering the data in the SPSS software، results were showed as specificity، sensitivity، positive and negative predictive value، and likelihood ratio. Twenty-three out of 30 patient with sputum positive and 12 patients with sputum negative have positive T-SPOT. The sensitivity، specificity، positive predictive value، negative predictive value، likelihood ratio were 76%، 40%، 56%، 63%، 1. 25 respectively. We could not differentiate between active and latent infection by using this test. Despite the high infectivity of tuberculosis in this region، this test would not help as a valuable diagnostic method because of the increased pulmonary infection other than TB and lower likelihood ratio.