To evaluate the performance of laboratorial tests in diagnosing tuberculosis in patients with clinical or radiological evidence of disease but with negative sputum.
Thirty-four patients with clinical (cough, fever, weigh loss) or radiological (micronodules, consolidation, cavitation, nodules) suspicion of pulmonary tuberculosis but having negative sputum were submmited to fiberoptic broncoscopy to obtain bronchoalveolar lavage (BAL). Sensitivity, Specificity, PPV and NPV of BAL smear, culture, PCR and ADA (cut-off 2.5 U/L); bronchial biopsy;smear and culture from induced sputum (collected after the BAL)and PPD were evaluated.
From the 34 patients with tuberculosis suspicion, only 22 (64.7%) had been confirmed the diagnosis. The performance of the tests is showed in the table bellow.
PPD and cultures (BAL and sputum) were the most sensitive methods for the diagnosis of pulmonary tuberculosis. However, due to the low specificity of the PPD, this test may be judged with criteria in places where there is high prevalence of tuberculosis.
The diagnosis of tuberculosis in patients with negative sputum is a clinical problem all over the world. The association of multiple laboaratory tests can improve the diagnosis field.
BAL smearBAL cultureBAL PCRBAL ADABronchial biopsyPos BAL smearPos BAL culturePPDSensituvity (%)13.666.73535.731.821.153.390Specificity (%)1001001006010010010014.3PPV(%)10010010054.510010010060.0NPV(%)38.757.148.030.044.455.553.350
Leila Antonangelo, None.