Feasibility of the TBDx automated digital microscopy system for the diagnosis of pulmonary tuberculosis

Abstract

BackgroundImproved and affordable diagnostic or triage tests are urgently needed at the microscopy centre level. Automated digital microscopy has the potential to overcome issues related to conventional microscopy, including training time requirement and inconsistencies in results interpretation.MethodsFor this blinded prospective study, sputum samples were collected from adults with presumptive pulmonary tuberculosis in Lima, Peru and Ho Chi Minh City, Vietnam. TBDx performance was evaluated as a stand-alone and as a triage test against conventional microscopy and Xpert, with culture as the reference standard. Xpert was used to confirm positive cases.FindingsA total of 613 subjects were enrolled between October 2014 and March 2015, with 539 included in the final analysis. The sensitivity of TBDx was 62·2% (95% CI 56·6–67·4) and specificity was 90·7% (95% CI 85·9–94·2) compared to culture. The algorithm assessing TBDx as a triage test achieved a specificity of 100% while maintaining sensitivity.InterpretationWhile the diagnostic performance of TBDx did not reach the levels obtained by experienced microscopists in reference laboratories, it is conceivable that it would exceed the performance of less experienced microscopists. In the absence of highly sensitive and specific molecular tests at the microscopy centre level, TBDx in a triage-testing algorithm would optimize specificity and limit overall cost without compromising the number of patients receiving up-front drug susceptibility testing for rifampicin. However, the algorithm would miss over one third of patients compared to Xpert alone.

Retrospective validation of MetaSystems’ deep-learning-based digital microscopy platform with assistance compared to manual fluorescence microscopy for detection of mycobacteria

“…Meanwhile, with its current performance, detected AFB-smear-positive slides would require review by manual microscopy for confirmation and semi-quantification. The adoption of such technology within an established AFB testing algorithm could help streamline the use of molecular detection assays, where nucleic acid amplification tests would be reserved for AFB-smear-positive samples identified digitally ( 9 , 16 , 17 ). Overall, a-DM has the potential to improve laboratory productivity by allowing redistribution of the workforce particularly in high-throughput laboratories with low incidence TB.…”

Automated Tuberculosis Detection and Analysis Using CXR’s Images

“…The designed system is best for identifying abnormality because of good sensitivity. A system was designed with automated tuberculosis detection procedure which was used for smear microscopy but it incorporated manual segmentation [5].Different variables from reference standard data were compared with algorithm results. Interpretation of algorithm was compared with reference standard technique results.…”

An automated smear microscopy system to diagnose tuberculosis in a high-burden setting

“…Automated smear microscopy provides an alternative to conventional manual smear microscopy (MS) for identifying acid-fast bacilli in sputum smears by offering speed and safety at potentially low cost with fewer technicians [6]. Automated systems enhance sensitivity by analysing a greater number of fields on microscopic slides than can be normally viewed manually by a technician [4].…”