PF4 and Sepsis: Five key proteins—β-actin (ACTB), fibronectin (FINC), metalloproteinase inhibitor 1 (TIMP1), platelet factor 4 (PF4), and C-X-C motif chemokine 7 (CXCL7)—were identified as significant discriminators of sepsis subgroups with AUCs ranging from 0.786 to 0.833.