Only two parameters are good enough to predict need for hospitalization with COVID-19: IL-6 and CRP 

Through case studies with over 80,000 samples, it was concluded that having both IL-6 ≥10 pg/mL and hs-CRP ≥10.0 mg/L very accurately predicts the need for hospitalization in COVID-19 positive patients. Only two parameters are good enough to predict.

In detail, Median IL-6 levels were the same in controls and outpatients but were about 75-fold higher in inpatients as compared to other groups (P<0.0001). Median hs-CRP levels were very similar in control subjects and outpatients but were about 80-fold higher in inpatients as compared to other groups (P<0.0001).

This is a report from a group of Boston Heart Diagnostics/Eurofins Scientific Network, USA, etc.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8191995/