DIAGNOSTIC IMPACT OF TBC PCR IN BRONCHIAL WASHING FOR THE DETECTION OF ACTIVE PULMONARY TB IN SMEAR NEGATIVE PATIENTS

Abstract

SESSION TITLE: Chest Infections 2 SESSION TYPE: Original Investigation Posters PRESENTED ON: 10/10/2018 01:00 PM - 02:00 PM PURPOSE: Diagnosis of pulmonary tuberculosis is not easy when the sputum smear for Mycobacterium tuberculosis(M.tbc) is negative or in the patients who can not expectorate effectively.The aim of the study has been that to evaluate the diagnostic impact of a commercially developed Tbc PCR test (Amplicor) in bronchial washings for detecting pulmonary tuberculosis in smear negative patients. METHODS: We recruited 205 patients whose sputum smear for M.Tbc were negative or who could not any sputum from January 2013 to December 2015. We performed bronchoscopy for acid-fast stain, culture of mycobacteria, and PCR test of bronchial washing if there were signs of hemoptysis, patients who could not cough up sputum, lung lesion that exclude pulmonary tuberculosis. RESULTS: Active pulmonary tuberculosis were identified in 136 patients. The number of male patients were65 and that of female patients were71. The mean age is 43.2 (16-86) years old. In underlying cormobidity, diabetes was most common disease in 25cases(18.3%). Active pulmonary tuberculosis combined with endobronchial tuberculosis and pleural effusion were identified in 28 cases (20.6%), 15 cases(11%), respectively. The sensitivity of bronchial washing smear, culture and AmplicorTbc PCR were 41.9%, 76.4%, 72.8%, respectively. The specificity and positive predictive values of bronchial washing for Tbc PCR were 96.2, 98.1%, respectively.In 130 cases, the sputum AFB smear was negative in 98 cases(72%) and the patients who could not any sputum were 38 cases(27.9%). The AFB smearand Tbc PCR of bronchial washing were the only diagnostic test in 31cases(22.8%), 64cases(47%) respectively. Therefore early diagnosis of pulmonary tuberculosis was possible by bronchial washing smear and PCR for M. tbc in 65cases(47.8%). In the 98 cases of sputum AFB smear negative M Tbc, the sensitivity of bronchial washing AFB smear, culture, PCR were 42.8%, 75.5%, 71.4%, respectively. In laboratory findings, CRP was significantly increased in sputum AFB culture positive group than negative group (7.65 vs 3.72mg/ml, P<0.05). CONCLUSIONS: Bronchial washing for AmplicorTbc PCR was effective nearly same as culture and rapid diagnostic method in patients who could not sputums expectorate effectively or smear negative pulmonary tuberculosis. CLINICAL IMPLICATIONS: Bronchoscopy and bronchial washing tbc PCR was effective diagnostic tool for sputum smear negative pulmonary tuberculosis. DISCLOSURES: No relevant relationships by Young Min Lee, source=Web Response