Of the 15 proteins that correlated directly, 13 are secreted through ER like CRTAC1—ALB, CFP, PGLYRP, ECM1, PI16, GSN, CLEC1B, HGFAC, APOD, TTR, GPLD1, F13B, and AHSG (GSN exists in cytoplasmic and secreted forms due to alternative splicing; we previously demonstrated that only the secreted form is decreased in plasma in severe COVID‐19 (Overmyer et al., 2021)). Here, ECM1 is linked to COVID-19.