Field evaluation of a blood based test for active tuberculosis in endemic settings

PLoS One. 2017 Apr 5;12(4):e0173359. doi: 10.1371/journal.pone.0173359. eCollection 2017.

Abstract

Over 9 million new active tuberculosis (TB) cases emerge each year from an enormous pool of 2 billion individuals latently infected with Mycobacterium tuberculosis (M. tb.) worldwide. About 3 million new TB cases per year are unaccounted for, and 1.5 million die. TB, however, is generally curable if diagnosed correctly and in a timely manner. The current diagnostic methods for TB, including state-of-the-art molecular tests, have failed in delivering the capacity needed in endemic countries to curtail this ongoing pandemic. Efficient, cost effective and scalable diagnostic approaches are critically needed. We report a multiplex TB serology panel using microbead suspension array containing a combination of 11 M.tb. antigens that demonstrated overall sensitivity of 91% in serum/plasma samples from TB patients confirmed by culture. Group wise sensitivities for sputum smear positive and negative patients were 95%, and 88%, respectively. Specificity of the test was 96% in untreated COPD patients and 91% in general healthy population. The sensitivity of this test is superior to that of the frontline sputum smear test with a comparable specificity (30-70%, and 93-99%, respectively). The multiplex serology test can be performed with scalability from 1 to 360 patients per day, and is amenable to automation for higher (1000s per day) throughput, thus enabling a scalable clinical work flow model for TB endemic countries. Taken together, the above results suggest that well defined antibody profiles in blood, analyzed by an appropriate technology platform, offer a valuable approach to TB diagnostics in endemic countries.

MeSH terms

  • Adult
  • Female
  • Hematologic Tests / methods*
  • Humans
  • Male
  • Mycobacterium tuberculosis / immunology
  • Plasma / microbiology
  • Sensitivity and Specificity
  • Serologic Tests / methods
  • Sputum / microbiology
  • Tuberculosis, Pulmonary / blood*
  • Tuberculosis, Pulmonary / diagnosis*
  • Tuberculosis, Pulmonary / microbiology
  • Young Adult

Grants and funding

The funder (NextGen In Vitro Diagnostics) provided support in the form of salary for author PG, but did not have any additional role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript. The specific roles of these authors are articulated in the ‘author contributions’ section.