Can Chromatography Distinguish Between COVID-19 and Other Diagnoses?

Covid-19 and SARS-CoV-2 are well and truly entrenched in our lives now. It is a year since they were first diagnosed in Wuhan, China and began their slow creep across the globe. The focus now is on providing healthcare to those suffering from Covid-19, vaccine research to help prevent others from getting infected and potentially becoming seriously ill, and better diagnosis to help those with the disease to get the treatment they need.

Researchers are focussing on all three of these strands in the fight to reduce Covid-19’s impact on society. A paper recently published by The Lancet - Diagnosis of COVID-19 by analysis of breath with gas chromatography-ion mobility spectrometry - a feasibility study – reports on work carried out by researchers in Scotland and Germany to provide a breathe test that can identify Covid-19 from a whole host of other respiratory conditions. A diagnosis that could become more significant as we move into the winter which traditionally brings with it a whole host of respiratory illnesses. And at the centre of the research lies chromatography.

Differentiate between Covid-19 and flu

Until researchers can deliver a suitable vaccine, the main fight against the Covid-19 pandemic can be summed up by the World Health Organization’s message to ‘test, test, test’. Testing will provide the best defence against the continued pandemic by allowing the best public health response allied with the optimum clinical response. This will become increasingly important as winter approaches and alongside Covid-19, medical professionals must fight influenza and other respiratory infections.

The current test for Covid-19 relies on a nasal or throat swab and quantitative reverse transcription polymerase chain reaction. The tests require authorised laboratories, take time to ship and process, and are also prone to false negative results. Medics need a point-of-care teat that is simple to administer and provides a quick diagnosis that can differentiate between Covid-19 and other respiratory conditions.

Chromatography spots the difference

Some researchers have proposed the use of gas chromatography with mass spectrometry or ion mobility spectrometry (GC-MS or GC-IMS) for the diagnosis of Covid-19 using breath samples. Previous work has shown that both influenza and acute respiratory distress syndrome can be identified using biomarkers in breath samples. And gas chromatography is ideal for analysing volatile samples as discussed in the article, Analysis and Identification of Mezcal and Tequila Aromas by Ambient Ionisation MS, GC-MS, and GCxGC-MS.

The team analysed breath samples from hospital patients in Scotland and Germany using gas chromatography. The patients were also checked for Covid-19 using the standard RT-qPCR test using nasal/throat swabs. The team report that:

These two studies independently indicate that patients with COVID-19 can be rapidly distinguished from patients with other conditions at first healthcare contact. The identity of the marker compounds is consistent with COVID-19 derangement of breath-biochemistry by ketosis, gastrointestinal effects, and inflammatory processes.