SERPING1 and COVID-19: Plasma protease C1 inhibitor (SERPING1) was the most significantly regulated protein (P‐value: 1.7*10−11; 1.5‐fold), and CD14 was the protein with the highest fold‐change (P: 2.4*10−10; 2.1‐fold) in COVID‐19 patients compared to PCR‐negative controls.