Sensitivity and specificity of an electronic nose in diagnosing pulmonary tuberculosis among patients with suspected tuberculosis

PLoS One. 2019 Jun 13;14(6):e0217963. doi: 10.1371/journal.pone.0217963. eCollection 2019.

Abstract

Objective: To investigate the potency of a hand-held point-of-care electronic-nose to diagnose pulmonary tuberculosis (PTB) among those suspected of PTB.

Methods: Setting: Lung clinics and Dr. Sardjito Hospital, Yogyakarta, Indonesia. Participants: patients with suspected PTB and healthy controls. Sampling: 5 minutes exhaled breath. Sputum-smear-microscopy, culture, chest-radiography, and follow-up for 1.5-2.5 years, were used to classify patients with suspected PTB as active PTB, probably active PTB, probably no PTB, and no PTB. After building a breath model based on active PTB, no PTB, and healthy controls (Calibration phase), we validated the model in all patients with suspected PTB (Validation phase). In each variable (sex, age, Body Mass Index, co-morbidities, smoking status, consumption of alcohol, use of antibiotics, flu symptoms, stress, food and drink intake), one stratum's Receiver Operating Characteristic (ROC)-curve indicating sensitivity and specificity of the breath test was compared with another stratum's ROC-curve. Differences between Area-under-the-Curve between strata (p<0.05) indicated an association between the variable and sensitivity-specificity of the breath test. Statistical analysis was performed using STATA/SE 15.

Results: Of 400 enrolled participants, 73 were excluded due to extra-pulmonary TB, incomplete data, previous TB, and cancer. Calibration phase involved 182 subjects, and the result was validated in 287 subjects. Sensitivity was 85% (95%CI: 75-92%) and 78% (95%CI: 70-85%), specificity was 55% (95%CI: 44-65%) and 42% (95%CI: 34-50%), in calibration and validation phases, respectively. Test sensitivity and specificity were lower in men.

Conclusion: The electronic-nose showed modest sensitivity and low specificity among patients with suspected PTB. To improve the sensitivity, a larger calibration group needs to be involved. With its portable form, it could be used for TB screening in remote rural areas and health care settings.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Breath Tests / instrumentation*
  • Case-Control Studies
  • Electronic Nose*
  • Female
  • Humans
  • Indonesia / epidemiology
  • Male
  • Middle Aged
  • Point-of-Care Systems
  • ROC Curve
  • Sensitivity and Specificity
  • Tuberculosis, Pulmonary / diagnosis*
  • Tuberculosis, Pulmonary / epidemiology
  • Young Adult

Grants and funding

AMIS, YWS, and NR were supported by the Directorate General of Higher Education of Indonesia, JWG and HO were supported by Devon Foundation, the Netherlands and The eNose Company, Zutphen, the Netherlands. The Directorate General of Higher Education of Indonesia and Devon foundation had no role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript. The eNose company provided support in the form of salaries for authors (JWG and HO), research materials (the Aeonose devices), study design, and data analysis, but did not have any additional role in the data collection, decision to publish, or preparation of the manuscript. The specific roles of these authors are articulated in the ‘author contributions’ section.