title: Intra-gastric string test: an effective tool for diagnosing tuberculosis in adults unable to produce sputum.
abstract: METHODS
  Tuberculosis (TB) diagnosis is challenging in patients who are unable to produce sputum. The string test, a method for retrieving enteropathogens, is a potential alternative diagnostic tool.
  
  
  OBJECTIVE
  To compare the TB detection yield and tolerability of the string test and that of sputum induction in adults with presumed TB in Uganda.
  
  
  METHODS
  Cross-sectional study. String test and sputum induction were performed consecutively in patients unable to produce sputum. The string was removed after a 2-h intra-gastric downtime. Sputum induction used nebulised 5% saline for 20 min. Light-emitting diode fluorescence microscopy, Löwenstein-Jensen and MGIT culture were performed on all specimens, and the Xpert(®) MTB/RIF assay on a subset. Tolerability questionnaires were administered.
  
  
  RESULTS
  Of 210 patients included in the study, 59% were human immunodeficiency virus (HIV) positive and 50 (23.8%) were diagnosed with TB. Of these, 48 (96.0%) were detected with the string test and 46 (92.0%) with sputum induction. In patients with specimens collected using both methods for paired analysis, the yield of microscopy detection with the string test was 13.8% (26/188) vs. 13.3% (25/188) with sputum induction (P = 1.0). The yield increased to 22.9% (42/183) using culture for string test vs. 24.6% (45/183) for sputum induction (P = 0.37). Xpert detected TB in 15/96 (15.6%) patients with the string test vs. 17/96 (17.7%) with sputum induction (P = 0.62). Tolerability was comparable.
  
  
  CONCLUSIONS
  The string test was well tolerated and provided similar yields to sputum induction, offering a viable alternative in resource-limited settings with minimal risk of transmission.
authors: Epicentre Mbarara Research Centre, Mbarara, Uganda.
authors: D
authors: D
authors: Atwine
authors: Epicentre Mbarara Research Centre, Mbarara, Uganda.
authors: M
authors: M
authors: Nansumba
authors: Epicentre Mbarara Research Centre, Mbarara, Uganda.
authors: P
authors: P
authors: Orikiriza
authors: Epicentre Mbarara Research Centre, Mbarara, Uganda.
authors: M
authors: M
authors: Riera
authors: Epicentre, Paris, France.
authors: F
authors: F
authors: Nackers
authors: Mbarara University of Science and Technology, Mbarara, Uganda.
authors: N
authors: N
authors: Kamara
authors: Epicentre Mbarara Research Centre, Mbarara, Uganda.
authors: P
authors: P
authors: Debeaudrap
authors: Epicentre Mbarara Research Centre, Mbarara, Uganda.
authors: Y
authors: Y
authors: Boum
authors: Epicentre Mbarara Research Centre, Mbarara, Uganda.
authors: M
authors: M
authors: Bonnet
mesh_terms: D000328:Adult; D001431:Bacteriological Techniques / Q000295:instrumentation* / Q000379:methods*; D016001:Confidence Intervals; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D018570:Risk Assessment; D013048:Specimen Handling / Q000379:methods*; D013183:Sputum / Q000382:microbiology; D013270:Stomach / Q000382:microbiology*; D014397:Tuberculosis, Pulmonary / Q000175:diagnosis*; D014454:Uganda; D055815:Young Adult