The accuracy of an electronic nose to diagnose tuberculosis in patients referred to an expert centre.

INTRODUCTION: An electronic nose (eNose) device has shown a high specificity and sensitivity to diagnose or rule out tuberculosis (TB) in the past. The aim of this study was to evaluate its performance in patients referred to INERAM. METHODS: Patients aged ≥15 years were included. A history, physical examination, chest radiography (CRX) and microbiological evaluation of a sputum sample were performed in all participants, as well as a 5-minute breath test with the eNose. TB diagnosis was preferably established by the gold standard and compared to the eNose predictions. Univariate and multivariate logistic regression analyses were performed to assess potential risk factors for erroneous classification results by the eNose. RESULTS: 107 participants with signs and symptoms of TB were enrolled of which 91 (85.0%) were diagnosed with TB. The blind eNose predictions resulted in an accuracy of 50%; a sensitivity of 52.3% (CI 95%: 39.6-64.7%) and a specificity of 36.4% (CI 95%: 12.4-68.4%). Risk factors for erroneous classifications by the eNose were older age (multivariate analysis: OR 1.55, 95% CI 1.10-2.18, p = 0.012) and antibiotic use (multivariate analysis: OR 3.19, 95% CI 1.06-9.66, p = 0.040). CONCLUSION: In this study, the accuracy of the eNose to diagnose TB in a tertiary referral hospital was only 50%. The use of antibiotics and older age represent important factors negatively influencing the diagnostic accuracy of the eNose. Therefore, its use should probably be restricted to screening in high-risk communities in less complex healthcare settings.

The potential of a portable, point-of-care electronic nose to diagnose tuberculosis.

INTRODUCTION: Tuberculosis (TB) is the leading cause of death due to an infectious disease worldwide. Especially in low-income countries, new diagnostic techniques that are accessible, inexpensive and easy-to-use, are needed to shorten transmission time and initiate treatment earlier. OBJECTIVE: We conducted a study with a handheld, point-of-care electronic nose (eNose) device to diagnose TB through exhaled breath. SETTING: This study includes a total of 110 patients and visitors of an expert centre of respiratory diseases in Asunción, Paraguay. TB diagnosis was established by culture of Mycobacterium tuberculosis complex and compared with the eNose results in two phases. RESULTS: The calibration phase, including only culture confirmed TB cases versus healthy people, demonstrated a sensitivity and specificity of 91% and 93% respectively. The confirmation phase, including all participants, showed a sensitivity of 88% and a specificity of 92%. The eNose showed high acceptance rate among participants, and was easy to operate. CONCLUSION: The eNose resulted in a powerful technique to differentiate between healthy people and TB patients. Its comfort, speed and usability promise great potential in vulnerable groups, in remote areas and hospital settings to triage patients with suspicion of TB.