Microclot analysis methodology. (A) Microclot Quantification: venous blood samples from critically ill patients and healthy controls were collected into sodium citrate tubes. PPP was isolated through centrifugation. PPP was incubated with ThT and the presence of microclots assessed using fluorescence microscopy. Software was trained to quantify microclots. (B) Microclot composition: after centrifugation of PPP, those from critically ill patients with microclots contained visible pellets that were not observed in patients without microclots or in healthy controls. The pellet was digested with trypsin and analyzed by mass spectrometry. (C) Amyloid-fibrin(ogen) colocalization: PPP was incubated with fluorescently labeled anti-fibrinogen antibody and ThT. Colocalization was assessed by fluorescence microscopy.