Fig. 1

Recruitment of patients, samples obtained, and resulting groups of patients for sample analysis. 134 patients were enrolled in the study. 7 patients were unable to produce at least one sample (either string or sputum) and were excluded. 5 patients were excluded as their cultures were contaminated. 5 samples had long delays in processing by lab (>12 days); these patients were excluded. 107 subjects submitted a sputum sample sufficient for evaluation by ZN, LJ, and MODS that that were included in the analysis. Additionally, 24 of these patients submitted both induced and spontaneous sputum sample for comparison. Of the 107 patients who submitted an adequate sputum sample, 92 also submitted a string sample. 10 additional patients submitted string sample but did not submit sputum sample. Of these102 patients that submitted a string test sample, 70 patients (68.6 %) were able to produce sputum spontaneously (“sputum productive”). 22 patients (21.5 %) were only able to produce a sputum sample after induction (“sputum-scarce”). Ten patients (9.8 %) were unable to produce any sputum (“sputum-absent”). While we note the results of these 10 string samples, these ten patients were not included in our larger analysis of TB diagnostic methods as there was no sputum for comparison