The variation in human blood serum metabolites resulting from an infection can assist in understanding mechanisms of pathogen action and body response and improve diagnosis.

To map serum signatures of hospitalized symptomatic patients, positive or negative to SARS-CoV-2.

Patients (n = 64) admitted to Anhembi Field Municipal Hospital, a hospital set up for initial care to patients with moderate symptoms, were analyzed being discriminated in positive (n = 32) or negative patients. Age and gender were matched to ensure homogeneity in the basal metabolic rates. Three Nuclear Magnetic Resonance (NMR) data set were recorded on Bruker AVANCE III 600 MHz spectrometer for serum samples analyzed in MetaboAnalyst 5.0 software platform.

The mean age of groups was 54.92 ±12.41 and 54.30 ±12.15, for positive and negative patients, divided in 16 female and 16 male. The ethnicity was 56.2% vs 46.8% caucasian, 34.3% mixed race in both groups, and 9.3% 12.5% vs black in positive and negative groups, respectively. BMI was 24 ±6.93 vs 33.5 ±7.85 in comparison to positive and negative patients, respectively. In both groups 50% of patients presented alveolar infiltrate.  Although the groups were not paired by comorbidities, they were homogeneous ensuring that the metabolic variation is due to COVID-19 as similar percentage of patients with arterial hypertension, diabetes and dyslipidemia. Clinical symptoms were also remarkably similar between the groups in relation to: fever, dry cough, dyspnea and myalgia. The Partial Least Squares - Discriminant Analysis (PLS-DA) performed onto noesy1d data discriminated positively from negative patients. Also, it covered lower variance. Combining NMR techniques, it was possible to depict the main metabolites that distinguished the COVID-19 signatures. Alanine, glucose, cholesterol, and glutamine were increased, and lactate decreased in COVID-19.

These results suggest NMR as an excellent tool to differentiate hospitalized patients with moderate symptoms as COVID-19 positive or negative. The Ethics Research Committee of the University of Campinas approved all of the experimental procedures, and all individuals signed the informed consent form.