[1] F1+2 levels can be quantified with blood tests and is used in the diagnosis of hyper- and hypocoagulable states and in the monitoring of anticoagulant therapy.
[4][3][1] The half-life of F1+2 is relatively long, which makes it more reliable for measuring ongoing coagulation than other markers like thrombin–antithrombin complexes and fibrinopeptide A.
[3] Levels of F1+2 have been reported to be elevated in venous thromboembolism, protein C deficiency, protein S deficiency, atrial fibrillation, unstable angina, acute myocardial infarction, acute stroke, atherosclerosis, peripheral arterial disease, and in smokers.
[6] Conversely, they do not appear to be increased with estetrol- or estradiol-containing birth control pills.
[6] However, F1+2 levels have been reported to be increased with oral estrogen-based menopausal hormone therapy, whereas transdermal estradiol-based menpausal hormone therapy appears to result in less or no consistent increase.