Solid-phase microextraction of sweat components of patients positive for Sars-Cov-2 for identification of possible biomarkers

Purpose Metabolome is gaining consideration as a viable approach to disease detection and even shows promising results in COVID-19 diagnosis. This work extends the study of the relationship between solid-phase microextraction (SPME) extractable sweat compounds (SPME-ECs) and COVID-19 positive patients. Methods Sweat samples were collected from 426 patients (126 positives and 300 negatives) recruited at Merida and Progreso (Yucatán, México) health centers. The composition of sweat was analyzed with a solid phase microextraction gas chromatography-mass spectrometry (SPME-GC-MS) method. Results The statistical analysis revealed significant differences between infected and non-infected patients’ SPME-EC profiles. Then, we evaluated different classification models to discriminate between positive and negative patients. The best model was the PLS-DA model, with percentages of specificity and sensitivity above 80%. Six relevant chromatographic peaks for the classification model were annotated (hexadecanoic acid, tetracosanoic acid, 6-hexadecenoic acid, oleic acid, squalene, and undecanal) based on the mass spectrum recognition using the NIST library (> 90% identity match). Palmitic and oleic acid signal was elevated in COVID-positive patients. While sapienic acid, lignoceric acid, squalene, and undecanal were detected in lower amount in COVID-positive patients. Conclusion The present list of chemical opens the possibility to be used as a reliable serologic biomarker.