Prospective study comparing the conventional and same-day strategies to diagnose pulmonary tuberculosis

The WHO recommends same-day sputum smear microscopy for the diagnosis of smear-positive tuberculosis (TB) in countries with high TB burden for earlier diagnosis and treatment, a cornerstone to prevent air-borne transmission. We aimed to compare the conventional strategy (sputum collection on three consecutive days) and the same-day strategy (hour h, h+1, h+2) in France, a country with low TB burden.

Over a six-month period, all adult individuals presenting with presumptive smear-positive TB were eligible for the study, registered in https://clinicaltrials.gov/ ID (NCT02961569). Sputum specimens were collected three times the first day, then once on the second day and once on the third day. The concordance between the two strategies regarding smears and cultures were assessed.

Of the 131 eligible individuals, 34 were given a TB treatment. Smears from hour h, h+1, h+2, day two and three were negative in 19 of these 34 patients. Positive smears were obtained in 15, 14, 15, 14, and 14 patients at hour h, h+1, h+2, on day two and three, respectively. Concordance regarding smear or culture was good, with Kappa 0.69 and 0.64, respectively.

The same-day strategy seems to be a good alternative to the conventional strategy.