title: Diagnostic yield of repeated smear microscopy examinations among patients suspected of pulmonary TB in Shandong province of China.
abstract: OBJECTIVE
  To analyse the yield of five repeated smear microscopy examinations for the diagnosis of smear-positive pulmonary tuberculosis (TB).
  
  
  METHODS
  Patients with respiratory symptoms and abnormal chest X-rays provided five spontaneous sputum samples for acid-fast bacilli (AFB) smear microscopy in one of nine county laboratories.
  
  
  RESULTS
  Of 9302 patients with respiratory symptoms and abnormal X-rays, 6437 (69%) had at least one smear-positive sputum. Of these, 84.5% were diagnosed on the first smear, 96.7% on the first two smears, and 99.9% on the first three sputum smears. The fourth and fifth sputum smears yielded only seven additional cases (0.1%).
  
  
  CONCLUSIONS
  Smear microscopy examination of two spontaneous sputum specimens is the most efficient, and three sputum smear examinations provide a diagnosis in almost all cases.
authors.affiliation: Shandong Center for Tuberculosis Control, Jinan, China. wuzhilei@sohu.com
authors.forename: Z L
authors.initials: ZL
authors.lastname: Wu
authors.forename: A Q
authors.initials: AQ
authors.lastname: Wang
mesh_terms: D002681:China; D006801:Humans; D012189:Retrospective Studies; D013183:Sputum / Q000382:microbiology*; D014397:Tuberculosis, Pulmonary / Q000175:diagnosis*