title: Detection Yield and Tolerability of String Test for Diagnosis of Childhood Intrathoracic Tuberculosis.
abstract: BACKGROUND
  Difficulty to obtain sputum in children complicates diagnosis of intrathoracic tuberculosis (TB). The intragastric string test (ST) used for retrieval of enteric pathogens might be an alternative specimen collection method but requires further evaluation of its utility in TB diagnosis. We conducted a cross-sectional study comparing the TB detection yield and the tolerability of ST and sputum induction (SI) in children.
  
  
  METHODS
  Two ST and SI procedures were performed in children (3-14 years of age) who were clinically suspected of having TB. The string was removed after a 2-hour gastric downtime, and SI was done after a maximum of 20 minutes nebulization with 5% saline solution. LED-fluorescence microscopy and mycobacterial cultures were performed on all specimens, and XpertMTB/RIF assay was performed on stored specimen sediments. Tolerability questionnaires were administered to parents of children.
  
  
  RESULTS
  Of 137 included children (median age: 8.1 years; 33.3% with HIV infection), 14 (10.2%) were diagnosed with TB, 10 (71.4%) by ST and 12 (85.7%) by SI. Among 105 children with both ST and SI performed, 5 (4.8%) versus 4 (3.8%) were smear positive using ST and SI, respectively (McNemar P = 1.00). Nine (8.6%) in each group had positive cultures (P = 1.00). Of 64 children tested with XpertMTB/RIF, 3 (4.7%) of the ST group versus 4 (6.3%) of the SI group were TB positive (P = 1.00). No adverse serious events were reported. ST could not be performed in 22 of 137 (16.1%) children because they were unable to swallow the capsule.
  
  
  CONCLUSIONS
  TB detection yield was comparable between ST and SI. The tolerability of ST in young children might be improved by the reduction of the size of the capsule.
authors.affiliation: From the *Epicentre Mbarara Research Centre, Uganda; †Mbarara University of Science and Technology, Uganda; ‡Epicentre Paris, France; and §IRD UMI233/INSERM U1175/Université de Montpellier, France.
authors.forename: Margaret
authors.initials: M
authors.lastname: Nansumba
authors.forename: Elias
authors.initials: E
authors.lastname: Kumbakumba
authors.forename: Patrick
authors.initials: P
authors.lastname: Orikiriza
authors.forename: Yolanda
authors.initials: Y
authors.lastname: Muller
authors.forename: Fabienne
authors.initials: F
authors.lastname: Nackers
authors.forename: Pierre
authors.initials: P
authors.lastname: Debeaudrap
authors.forename: Yap
authors.initials: Y
authors.lastname: Boum
authors.forename: Maryline
authors.initials: M
authors.lastname: Bonnet
mesh_terms: D000293:Adolescent; D001431:Bacteriological Techniques / Q000379:methods*; D002648:Child; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D003955:Diagnostic Tests, Routine / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D009161:Mycobacterium / Q000302:isolation & purification*; D010342:Patient Acceptance of Health Care; D012680:Sensitivity and Specificity; D013048:Specimen Handling / Q000379:methods*; D013183:Sputum / Q000382:microbiology; D013270:Stomach / Q000382:microbiology*; D014397:Tuberculosis, Pulmonary / Q000175:diagnosis*