Some people get infected with the coronavirus and never show any symptoms, while others get so sick they require urgent hospitalization in an intensive care unit. Clearly, people can respond very differently to the infection, and a new study suggests that hints of this individual variation may be found in patients’ blood.

Researchers at the Charité Universitätsmediz in Berlin employed state-of-the-art analytical techniques to determine the levels of various proteins found in blood plasma from 31 men and women who received treatment for COVID-19 at varying degrees of severity.

A total of 27 blood proteins were associated with disease severity. These proteins include clotting factors and regulators of inflammation. For instance, some proteins act on interleukin 6, a molecule that is associated with severe COVID-19 symptoms.

These biomarkers were then assessed in samples from another group of 17 COVID-19 patients and a control group of 15 healthy people to validate how well levels of these proteins could predict disease outcome.

In turned out that the protein expression signatures could precisely classify patients according to the World Health Organization’s criteria for COVID-19.

“These results lay the foundations for two very different applications. One possible future use would be for disease prognosis,” explained Prof. Dr. Markus Ralser, the Director of Charité’s Institute of Biochemistry, who is also group leader at the Francis Crick Institute in London.

“An early blood test would enable the treating physician to predict whether or not a patient with COVID-19 will develop severe symptoms. This could potentially save lives: the sooner physicians know which patients will require intensive care, the faster they can make use of the available treatment options.”

COVID-19 is a very tricky disease to manage due to the high degree of uncertainty and individual variation. But if there was a way to assess how a patient’s pathology progresses in an objective manner, doctors would be certainly better equipped to provide proper treatment and perhaps save lives.

This is why a patient’s biomarker profile is so valuable — it can paint an accurate story of how the patient’s disease is progressing, regardless of their symptoms.

In the not so distant future, blood tests could become a common in-hospital diagnostic tool for COVID-19. If a patient has ‘hot’ biomarkers, a doctor could immediately transfer the patient to an intensive care unit.

Next, the researchers plan on validating their biomarker diagnostic method with a larger number of patients.

The findings were reported in the journal Cell.