title: Predictive factors for tuberculosis in patients with a TB-PCR-negative bronchial aspirate.
abstract: OBJECTIVE
  Pulmonary tuberculosis (PTB), with a tuberculosis (TB)-polymerase chain reaction (PCR)-negative bronchial aspirate (BA), but a positive culture result is often encountered in clinical practice. However, limited data are available concerning clinical judgment in patients with suspected PTB and a TB-PCR-negative BA pending culture results. The present study aimed to identify predictors for PTB in patients with a TB-PCR-negative BA.
  
  
  METHODS
  A retrospective study was conducted on patients who had undergone a bronchoscopy because of suspected PTB. Clinical, laboratory, and computed tomography (CT) findings were investigated in PTB patients with TB-PCR-negative but positive culture BA results, and non-PTB patients with a radiographic lesion comparable to the former.
  
  
  RESULTS
  Of 250 patients screened, 31 (12 %) were diagnosed with PTB by positive culture results only. Of these 31 patients, 30 (97 %) had a lesion within one-third of the hemithorax as determined by chest radiography. In the final analysis of 30 PTB and 65 non-PTB patients with comparable radiographic lesions, a positive QuantiFERON-TB Gold In-Tube (QFT) result was independently associated with an increased risk of a positive TB culture. CT findings of consolidation were a negative predictor for PTB. Patients with a negative QFT result and consolidation had a negative predictive value of 95 % for PTB, while patients with a positive QFT result and nodular CT abnormalities without consolidation had a positive predictive value of 86 % for PTB.
  
  
  CONCLUSIONS
  The simple combination of CT findings of consolidation and QFT test results may help clinicians to refine decision-making in patients with a TB-PCR-negative BA.
authors.affiliation: Department of Internal Medicine, School of Medicine, Kyungpook National University, Daegu, South Korea. kimch@knu.ac.kr
authors.forename: C H
authors.initials: CH
authors.lastname: Kim
authors.forename: J K
authors.initials: JK
authors.lastname: Lim
authors.forename: S Y
authors.initials: SY
authors.lastname: Lee
authors.forename: D I
authors.initials: DI
authors.lastname: Won
authors.forename: S I
authors.initials: SI
authors.lastname: Cha
authors.forename: J Y
authors.initials: JY
authors.lastname: Park
authors.forename: W K
authors.initials: WK
authors.lastname: Lee
authors.forename: J
authors.initials: J
authors.lastname: Lee
mesh_terms: D000328:Adult; D000368:Aged; D001999:Bronchoscopy; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009169:Mycobacterium tuberculosis / Q000235:genetics* / Q000302:isolation & purification; D016133:Polymerase Chain Reaction; D011379:Prognosis; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed; D014397:Tuberculosis, Pulmonary / Q000175:diagnosis*