title: Evaluation of a diagnostic algorithm for sputum smear-negative pulmonary tuberculosis in HIV-infected adults.
abstract: BACKGROUND
  The Revised National TB Control Program bases diagnosis of tuberculosis (TB) on sputum smear examination and response to a course of antibiotics, whereas World Health Organization recommends early chest radiography [chest x-ray (CXR)] for HIV-infected symptomatic patients. We evaluated the utility of initial CXR in the diagnostic algorithm for symptomatic HIV-infected patients with negative sputum smears.
  
  
  METHODS
  HIV-infected ambulatory patients with cough or fever of ≥2 weeks and 3 sputum smears negative for acid-fast bacilli were enrolled in Chennai and Pune, India, between 2007 and 2009. After a CXR and 2 sputum cultures, a course of broad-spectrum antibiotics was given and patients were reviewed after 14 days. Sensitivity, specificity, positive and negative predictive values of symptoms, CXR, and various combinations for diagnosing pulmonary tuberculosis (PTB) were determined, using sputum culture as gold standard.
  
  
  RESULTS
  Five hundred four patients (330 males; mean age: 35 years; median CD4: 175 cells per cubic millimeter) were enrolled. CXR had a sensitivity and specificity of 72% and 57%, respectively, with positive predictive value (PPV) of 21% and negative predictive value (NPV) of 93% to diagnose PTB. TB culture was positive in 49 of 235 patients (21%) with an abnormal initial CXR and 19 of 269 patients (7%) with a normal CXR (P < 0.001). Sensitivity and specificity of cough ≥2 weeks for predicting PTB was 97% and 6%, with PPV and NPV of 14% and 94%, respectively.
  
  
  CONCLUSIONS
  Although moderately sensitive, basing a diagnosis of TB on initial CXR leads to overdiagnosis. An absence of weight loss had a high NPV, whereas none of the combinations had a good PPV. A rapid and accurate diagnostic test is required for HIV-infected chest symptomatic.
authors.affiliation: National Institute for Research in Tuberculosis, Chennai, India.
authors.forename: Chandrasekaran
authors.initials: C
authors.lastname: Padmapriyadarsini
authors.forename: Srikanth
authors.initials: S
authors.lastname: Tripathy
authors.forename: Lakshmanan
authors.initials: L
authors.lastname: Sekar
authors.forename: Perumal Kannabiran
authors.initials: PK
authors.lastname: Bhavani
authors.forename: Nitin
authors.initials: N
authors.lastname: Gaikwad
authors.forename: Srinivasan
authors.initials: S
authors.lastname: Annadurai
authors.forename: Gopalan
authors.initials: G
authors.lastname: Narendran
authors.forename: Nagamiah
authors.initials: N
authors.lastname: Selvakumar
authors.forename: Arun R
authors.initials: AR
authors.lastname: Risbud
authors.forename: Dinesh
authors.initials: D
authors.lastname: Sheta
authors.forename: Sikhamani
authors.initials: S
authors.lastname: Rajasekaran
authors.forename: Aleyamma
authors.initials: A
authors.lastname: Thomas
authors.forename: Fraser
authors.initials: F
authors.lastname: Wares
authors.forename: Soumya
authors.initials: S
authors.lastname: Swaminathan
mesh_terms: D000328:Adult; D000465:Algorithms; D018791:CD4 Lymphocyte Count; D005260:Female; D015658:HIV Infections / Q000150:complications*; D006801:Humans; D008168:Lung / Q000000981:diagnostic imaging*; D008297:Male; D011859:Radiography; D012680:Sensitivity and Specificity; D013183:Sputum / Q000382:microbiology*; D014397:Tuberculosis, Pulmonary / Q000150:complications / Q000175:diagnosis* / Q000000981:diagnostic imaging*