FIND and APVS Launch TBDx™ Feasibility Evaluation in Peru

The mission of the Foundation for Innovative New Diagnostics (FIND) is to assist in the development and deployment of accurate and affordable diagnostic tests for poverty-related diseases in developing countries. In March, FIND and APVS entered into a collaboration agreement to evaluate the feasibility of automated sputum microscopy and the performance characteristics of using TBDx™ in detecting tuberculosis. The first of two projects started this week at the Instituto de Medicina Tropical Alexander von Humboldt, Universidad Peruana Cayetano Heredia, in Lima, Peru. The principal investigator is Dr. Eduardo Gotuzzo.  Managing the project study for FIND will be Dr. Pamela Nabeta.

The primary objectives of the study:

  • Determine the sensitivity, specificity, and predictive values of TBDx™ among adult TB suspects, using culture as the gold standard;
  • Compare the performance of TBDx™ to routine laboratory LED Fluorescent Microscopy (LED/FM); and,
  • Determine the feasibility of using the TBDx™ system at a high workload reference laboratory.

Secondary objectives:

  • Determine the minimal training requirements;
  • Determine the time to result compared to routine LED/FM;
  • Assess performance variations between direct and concentrated smears;
  • Determine the performance of TBDx™ in combination with Xpert MTB/RIF;
  • Assess the ease-of-use, hands-on time and perceived benefits; and,
  • Identify potential challenges to implementation.

Tosh Sondh, APVS Director of Engineering, met with study team officials and set-up the TBDx™ system in the university laboratory. Over a 4-day period he conducted extensive training sessions with multiple staff members.  The training, when combined with the APVS provided Field Manuals, will assist in the successful execution of the study project. The TBDx™ system will be connected to the internet to assist in remote trouble shooting, if necessary.

Unique Aspects of the FIND Evaluation

The FIND evaluation presents two unique aspects in the evaluation of the TBDx™ platform:

  • This is the first time the TBDx™ system will be evaluated using a 4-slide automated slide stage. The two previous studies, South Africa and Nigeria, have involved a 200-slide automated slide loader, a product configuration especially useful for high volume TB reference laboratories. The 4-slide configuration is intended for routine hospital and clinic settings. Though the operational software versions change slightly between the two configurations, the image analysis processing and the detection algorithms remain unchanged.
  • In a recent study comparing the preparation of slides using concentrated vs. direct techniques it has been reported that sputum concentration can increase diagnostic sensitivity. The feasibility studies will involve a TBDx™ performance evaluation using BOTH concentrated AND direct sputum smear techniques.
  • In South Africa all slides were stained from concentrated sputum, and the results were reported in an earlier blog. In Nigeria, all slides were prepared using a directly applied smear. Preliminary results will be reported at the 45th Union World Conference on Lung Health later this month in Barcelona.

The success of these two feasibility projects, combined with the performance characteristics of two previous studies in South Africa and Nigeria, will move TBDx™ closer to becoming the first WHO-accepted Automated Sputum Microscopy diagnostic technology.

The Lima, Peru study likely will conclude in February 2015.  A second study in Hanoi, Vietnam is scheduled to begin in mid-December.

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