Lonestar VOC Analyzer

Reproducibility is key for any analytical technique, and extensive testing has been carried out to ensure that the Lonestar VOC Analyzer, when used with the ReCIVA Breath Sampler, allows for consistent collection and analysis of breath VOCs. This is of particular importance when conducting studies that involve the collection of multiple samples, at multiple different sites and timepoints, such as Owlstone Medical's LuCID trial.

The figure to the left shows chromatograms of VOCs in breath samples collected on independent VOC sample tubes using the ReCIVA Breath Sampler and analyzed using the Lonestar VOC Analyzer. High reproducibility is observed within a single breath collect (i and ii). Small changes in the chromatogram are observed between different breath collects performed on the same individual (iii), which is to be expected because some VOCs in breath do vary over time.

A model (such as the OPLS-DA model, left) or classification algorithm is then developed and applied to the reduced data set. This algorithm tests relevant features of the data, and assigns each sample to the disease or disease-free category. The form of the classifier depends upon the data-set, but random forest, sparse logistic regression and support vector machines have all been successfully deployed. The classifier is then ideally tested on a new set of samples, to externally validate the sensitivity and specificity.