Components of the Hemostatic System
in Plasma 3
Proteins 4 5
PAI-3 (Protein C Inhibitor)
Rises during pregnancy in 2nd
Decreases during pregnancy
Common names may be of primarily historical significance. The factor nomenclature was devised to reduce the number of synonyms for the same component which had made description of the process of
coagulation unnecessarily awkward.
2 Plasma coagulation factors are all designated by Roman numerals, platelet factors by Arabic numerals.
3 Concentration is given for the common situation in which 9 volumes of blood collected are collected into one volume of anticoagulant solution. The anticoagulant dilutes the plasma, but does not affect
the volume of the red blood cells. As a consequence of this, concentrations are dependent on the hematocrit, a consideration of clinical importance in polycythemic patients.
4Protein structure and gene databases can be found at many locations on the World Wide Web. A few are: http://www.ncbi.nlm.nih.gov/, http://www.gdb.org/, http://www.hgmp.mrc.ac.uk/,
http://www.ebi.ac.uk/ebi_home.html, http://www.expasy.ch, http://www.biochem.ucl.ac.uk/bsm/pdbsum/, http://www.rcsb.org/.
5 Color indicates that the factor is a vitamin K-dependent protein.
6 Factor III is used as a synonym for thromboplastin, the mixture of tissue factor and phospholipid.
7 Discovered to be the the activated form of Factor V after the numeral had been assigned.
8The molar concentration of vWF is difficult to express because of the many different polymeric forms that vary in mol wt from 500,000 to 20 x 106 7
9 Assumes a platelet volume of 1 x 10-14 L.