Diagnosing Bacterial Respiratory Tract Infections via Novel Mobile Spectrometer

Lung infection concept illustration
Lung infection concept illustration
A gas-capillary column ion mobility spectrometer may be a feasible and noninvasive tool for clinicians to diagnose respiratory tract infections in hospitalized patients.

Gas-capillary column ion mobility spectrometer (GC-IMS) analysis of exhaled volatile organic compounds (VOC) may be a noninvasive and feasible option for clinicians to diagnose respiratory tract infections (RTIs) in hospitalized individuals, according to a study published in PLoS One.

Researchers identified and recruited 71 individuals at the Royal Liverpool University Hospital in the United Kingdom to participate in a prospective study to determine the feasibility and accuracy of a portable GC-IMS to diagnose bacterial RTIs, which would assist in decreasing the inappropriate use of antibiotic therapy. In addition, the current gold standard for VOC detection is gas chromatography/mass spectrometry, but these devices have several disadvantages (eg, expensive, large, and typically laboratory-based).

Individuals were asked to inhale and then exhale into a disposable mouthpiece that was attached directly to a machine mounted on a hospital trolley and brought to their bedside for data collection to be downloaded and reviewed. Study results demonstrated test sensitivity and specificity rates of 62% (95% CI, 41%-80%) and 80% (95% CI, 64%-91%), respectively.

Limitations of this study include the small sample size, single research site, and overall exploratory nature. In addition, there was a low rate of microbiologic testing that could have caused a selection bias, as patients with confirmed viral diagnosis through laboratory services were recruited to participate in the study because of a low number of participants confirmed with viral RTIs.

The researchers concluded that the use of a portable GC-IMS instrument by clinicians to test for and diagnose bacterial RTI in hospitalized patients was an overall feasible option, with moderate accuracy (area under the curve, 0.73; 95% CI, 0.61-0.86). However, further instrument testing is needed.

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Lewis JM, Savage RS, Beeching NJ, Beadsworth MBJ, Feasey N, Covington JA. Identifying volatile metabolite signatures for the diagnosis of bacterial respiratory tract infection using electronic nose technology: a pilot study. PLoS One. 2017;12(12):e0188879.