To measure the severity of COVID-19, researchers create a tool that can pull an elusive marker from human blood

When COVID-19 attacks, the immune system produces a cytokine, or protein, called Interleukin-6 (IL-6), whose concentrations can offer vital information about a patient’s level and stage of infection.

But measuring the critical marker has been extremely challenging, given its nearly undetectable presence in the biological stew that makes up human blood. Existing technology has not been accurate or sensitive enough to measure concentrations of IL-6 well enough to be reliable, especially in low concentrations….

https://brighterworld.mcmaster.ca/articles/to-measure-the-severity-of-covid-19-researchers-create-a-tool-that-can-pull-an-elusive-marker-from-human-blood/