Normal chest radiography in pulmonary tuberculosis: implications for obtaining respiratory specimen cultures

Int J Tuberc Lung Dis. 2008 Apr;12(4):397-403.


Setting: Urban tuberculosis (TB) clinic, Nashville, Tennessee, USA.

Objective: Chest radiographs (CXRs) help in the diagnosis of pulmonary TB, but may be normal. Mycobacterium tuberculosis in culture is diagnostic of TB, but cultures are not routinely obtained in resource-poor settings. We examined rates and risk factors for pulmonary TB associated with normal CXR.

Design: An observational cohort study was performed among all respiratory culture-positive TB cases referred to the Nashville Health Department from October 1992 to July 2003. Clinical factors, demographics and underlying medical conditions were assessed.

Results: Of 601 study patients, 53 (9%) had normal CXRs: 31/138 (22%) were human immunodeficiency virus (HIV) infected and 22/463 (5%) were non-HIV-infected/unknown (P<0.001). Among HIV-infected patients, normal CXR was more likely in persons with renal failure (13% vs. 3%, P=0.048). Among non-HIV-infected/unknown patients, normal CXR was more likely in those who were asymptomatic at presentation (32% vs. 13%, P=0.022). In multivariable logistic regression analysis, HIV infection was associated with an increased risk of normal CXR (odds ratio [OR] 6.61, P<0.0001); factors associated with reduced risk were dyspnea (OR 0.24, P=0.026), positive sputum smear (OR 0.45, P=0.028) and cough (OR 0.48, P=0.038).

Conclusions: The rate of normal CXR among persons with culture-confirmed pulmonary TB was high. Respiratory specimen cultures should be obtained in TB suspects with a normal CXR, particularly HIV-infected persons.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • AIDS-Related Opportunistic Infections / diagnosis
  • AIDS-Related Opportunistic Infections / diagnostic imaging*
  • AIDS-Related Opportunistic Infections / epidemiology
  • Adult
  • Cohort Studies
  • Female
  • HIV Infections / complications
  • HIV Infections / epidemiology
  • Humans
  • Male
  • Mass Chest X-Ray
  • Middle Aged
  • Mycobacterium tuberculosis / isolation & purification*
  • Retrospective Studies
  • Sputum / microbiology*
  • Tuberculosis, Pulmonary / complications
  • Tuberculosis, Pulmonary / diagnosis
  • Tuberculosis, Pulmonary / diagnostic imaging*
  • Tuberculosis, Pulmonary / epidemiology