Fibrinogen estimation can not be done by serum
FIBRINOGEN HAS A MOLECULAR WEIGHT OF 3,40,000 D AND IS SYNTHESIZED BY THE LIVER.FIBRINOGEN LEVEL IN BLOOD IS 200-400 MG/DL
SERUM IS OBTAINED AFTER BLOOD CLOTTING, DURING WHICH FIBRINOGEN IS CONVERTED INTO FIBRIN AS PART OF THE CLOTTING PROCESS.
WHEN WE REMOVE BLOOD CLOTT WE ALSO REMOVE FIBRINOGEN IN THE CLOTT.
SO THAT , WE ARE NOT ABLE TO ESTIMATE FRIBRENOGEN FROM SERUM