title: An incremental cost-effectiveness analysis of the first, second and third sputum examination in the diagnosis of pulmonary tuberculosis.
abstract: METHODS
  St. Francis Hospital in Katete District, Eastern Province, Zambia.
  
  
  OBJECTIVE
  To compare the incremental cost-effectiveness of examining serial sputum smears for screening suspects for pulmonary tuberculosis at a rural district hospital in Zambia.
  
  
  METHODS
  An incremental cost-effectiveness analysis of serial sputum smear examinations for diagnosing pulmonary tuberculosis based on laboratory results collected during 1997 and 1998 in a rural district hospital in Zambia. The cost analysis took a health service provider perspective, and used the ingredients approach. The cost-effectiveness is expressed in terms of the incremental cost per tuberculosis case diagnosed. Relevant information was obtained from various sources, including administrative records, interviews and direct observation.
  
  
  RESULTS
  Of a total of 166 acid-fast bacilli positive suspects who had three sputum smears examined sequentially, 128 (77.1%) were found on the first smear, a further 25 (15%) on the second smear and 13 (7.9%) additional cases were identified on the third smear. The economic analysis shows that the incremental cost of performing a third test, having already done two, increases rapidly with only a small gain in terms of additional cases of tuberculosis identified.
  
  
  CONCLUSIONS
  A policy of examining two samples should be considered in resource-poor settings, if the remaining steps of the national diagnostic algorithm can be adhered to with respect to smear-negative suspects.
authors.affiliation: London School of Hygiene & Tropical Medicine, UK.
authors.forename: D
authors.initials: D
authors.lastname: Walker
authors.forename: R
authors.initials: R
authors.lastname: McNerney
authors.forename: M K
authors.initials: MK
authors.lastname: Mwembo
authors.forename: S
authors.initials: S
authors.lastname: Foster
authors.forename: V
authors.initials: V
authors.lastname: Tihon
authors.forename: P
authors.initials: P
authors.lastname: Godfrey-Faussett
mesh_terms: D017281:Cost of Illness; D003362:Cost-Benefit Analysis; D006801:Humans; D013183:Sputum / Q000382:microbiology*; D014397:Tuberculosis, Pulmonary / Q000175:diagnosis* / Q000191:economics*; D015024:Zambia