FTIR-Based Saliva Test Detects Body’s Response to COVID-19

By LabMedica International staff writers
Posted on 11 Mar 2022

Image: Agilent Cary 630 FTIR spectrometer (Photo courtesy of Agilent Technologies Inc.)

A potential new saliva test can rapidly detect COVID-19 infection and may even indicate if a person is likely to become seriously unwell by reading the chemical signature in a person’s saliva. The researchers found the test worked by detecting the body’s response to COVID-19 rather than just the virus itself – making it different from PCR and rapid antigen tests. In addition, the researchers also established a decontamination procedure that would allow infected samples to be safely handled and tested on the spot.

In a study, researchers at the QIMR Berghofer Medical Research Institute (Brisbane, Australia) collaborated with Agilent Technologies Inc. (Santa Clara, CA, USA) on a proof-of-concept FTIR-based saliva COVID-19 testing workflow using the Agilent Cary 630 FTIR Spectrometer. The study investigated the pathophysiological response to a COVID-19 infection through ATR-FTIR spectroscopy. The researchers acquired infrared spectra of saliva samples following a quick and simple sample preparation requiring only ethanol and basic laboratory equipment. An infrared spectrum can be considered as a biochemical snapshot of the saliva sample including a COVID-19 immune response signature. Unlike other testing technologies such as PCR testing or rapid antigen test, the ATR-FTIR method analyses the pathophysiological responses of the human body rather than detecting the pathogen/antigen itself, which is thought to make this method more robust against virus mutations.

“We applied a simple ethanol decontamination procedure for biosafe handling of self-collected saliva samples. A basic step of significant importance for any test that has the potential to be used in non-clinical environments such as in remote areas or in scenarios where large crowds require rapid testing, for example, in airports, or sports stadiums,” explained associate professor Michelle Hill, head of QIMR Berghofer’s Precision and Systems Biomedicine Research Group, and one of the lead scientists of the study.

“Earlier research studies on ATR-FTIR for COVID-19 saliva testing were not conclusive on the biological basis for the saliva testing methodology. To shine a light on this aspect, we also conducted controlled infection experiments on cells and mice models and established the most characteristic COVID-19 positive spectral signature. We integrated our data from in vitro cell studies, in vivo mouse studies, and independent human cohort studies, as well as data from recent publications to demonstrate the robustness of the methodology,” Hill added.

“We are very excited about this research study. FTIR spectroscopy is an easy-to-use analytical technique, uses minimal consumables, and provides results in seconds,” said Andrew Hind, associate vice president of Research and Development for the Molecular Spectroscopy Division at Agilent. “It emphasizes the potential of ATR-FTIR spectroscopy for life science and infectious disease research. Agilent funded parts of this research work through the Agilent Technologies Applications and Core Technology - University Research Grant and provided the Cary 630 FTIR Spectrometer. We will continue to support work in the field of COVID-19 and infectious diseases research.”