Reference Range
Factor IX (plasma thromboplastin component [PTC]) is produced in the liver. It is a single-chain zymogen with a molecular weight of 57 kd and a plasma half-life of 18-24 hours. It binds effectively to collagen not only in vitro
but also, apparently, in vivo, and this may account for the finding that when factor IX is infused into hemophilia B patients, recovery is only 50% of what was expected.
The reference range for factor IX is between 60% and 140% of normal values.