title: Number of sputum specimens during treatment follow-up of tuberculosis patients: two or one?
abstract: METHODS
  National Institute for Research in Tuberculosis clinics in Chennai and Madurai, India.
  
  
  OBJECTIVE
  To examine the pattern of serial smears (negative-negative [NN], negative-positive [NP], positive-negative [PN], positive-positive [PP]) during treatment follow-up of culture-confirmed new smear-positive tuberculosis (TB) patients, and the proportion of culture-negatives in each category.
  
  
  METHODS
  We reviewed the records and extracted follow-up smear (fluorescent microscopy) and culture (Löwenstein-Jensen) results of patients enrolled in clinical trials from January 2000 to August 2012 and treated with the Category I regimen (2EHRZ3/4HR3). Data entry and analysis were performed using EpiData.
  
  
  RESULTS
  Among 520 patients (176 infected with the human immunodeficiency virus), the proportions of culture-negative patients with NN, discordant (PN or NP) and PP patterns were approximately 98%, 80% and 40%, respectively. The smear-positive culture-negative phenomenon was more frequent in follow-up smear results graded 1+, followed by 2+ and 3+.
  
  
  CONCLUSIONS
  There is justification for discontinuing the examination of second specimens during treatment follow-up among TB patients. However, a positive result on the first smear needs to be confirmed by a second positive result before making clinical management decisions. The World Health Organization may need to reconsider its recommendation on this issue.
authors.affiliation: National Institute for Research in Tuberculosis, Chennai, India.
authors.forename: R S
authors.initials: RS
authors.lastname: Kumar
authors.affiliation: International Union Against Tuberculosis and Lung Disease, South-East Asia Office, New Delhi, India.
authors.forename: A M V
authors.initials: AM
authors.lastname: Kumar
authors.affiliation: Desmond Tutu TB Centre, Department of Paediatrics and Child Health, Stellenbosch University, Cape Town, South Africa.
authors.forename: M
authors.initials: M
authors.lastname: Claassens
authors.affiliation: National Institute for Research in Tuberculosis, Chennai, India.
authors.forename: V V
authors.initials: VV
authors.lastname: Banurekha
authors.affiliation: National Institute for Research in Tuberculosis, Chennai, India.
authors.forename: N S
authors.initials: NS
authors.lastname: Gomathi
authors.affiliation: National Institute for Research in Tuberculosis, Chennai, India.
authors.forename: P
authors.initials: P
authors.lastname: Venkatesan
authors.affiliation: National Institute for Research in Tuberculosis, Chennai, India.
authors.forename: S
authors.initials: S
authors.lastname: Swaminathan
keywords: culture-negative; pulmonary TB; smear-positive; sputum culture; sputum smear