F10 and antiphospholipid syndrome: Furthermore, in patients with antiphospholipid syndrome, the presence of antiphospholipid antibodies has been shown to falsely raise anti-FXa levels due to a direct inhibition of specific FXa activity in a chromogenic assay [64]; in addiction, due to cytokine release syndrome or propofol use, many critically ill patients also develop hypertriglyceridemia, which has also been shown to falsely increase anti-FXa levels [65].