All samples were tested with TBDx and compared with smear microscopy and Xpert MTB/RIF using solid and liquid culture as gold standard.

Operators were blinded to all other results for a sample upon data entry.

The TBDx is an automated platform is based on an Olympus BX41 microscope with a 40 x objective lens, fitted with an Olympus XC 10 colour camera and a movable slide stage, with an attached computer that receives high-quality digital images acquired from the camera. The computer then operates detection algorithms that segment, evaluate, and classify objects of interest in these images which can be stored for subsequent review. The platform is able to integrate an optional 200-slide automated slide loader for high volume settings. The application can capture 100, 300 or more digital fields-of-view and can provide results for positive or negative smears in 5 minutes or less.

Sensitivity, specificity and predictive values of TBDx compared to two solid (Löwenstein Jensen) and two liquid (MGIT) cultures

Two days of hands-on, onsite TBDx training was provided to laboratory technicians with prior experience using smear microscopy, followed by 1-day observation. Each operator performed 3-4 runs under supervision and a proficiency assessment was conducted prior to study initiation. Following study completion all technicians were given a survey to assess perception of training needs and ease of use.