Severe Covid-19 patients have unique phenotype
science.sciencemag.org
science.sciencemag.org
https://dxterity.com/interferon-type-1/#:~:text=The%20IFN%2D....
A quick search indicates there might be something comparable from the usual mass-market retail labs (Quest, LabCorp).
"Based on our study, we propose that type I IFN deficiency is a hallmark of severe COVID-19 and infer that severe COVID-19 patients might be potentially relieved from the IFN deficiency by IFN administration and from exacerbated inflammation by adapted anti-inflammatory therapies targeting IL-6 or TNF-α, a hypothesis worth cautious testing."