Fibrin monomers are monomers of fibrin which are formed by the cleavage of fibrinogen by thrombin. Levels of fibrin monomers can be measured using blood tests and can serve as a marker of in vivo fibrinogenesis and coagulation activation. They may be useful in the evaluation hypercoagulability.
Levels of fibrin monomers may be increased with pregnancy and by estrogen-containing combined birth control pills.