When looking at COVID-19 specific factors, infection prior to 2021 compared to July-December 2021, and symptom duration 8–10 days compared to less than 5 days, NIV/HFNC, eGFR < 60, higher N-Ag quanterix, higher CRP, and D-dimer > 0.93 were associated with D0 lymphopenia. This evidence concerns the gene CRP and COVID-19.