Starting in 1955, renaming of coagulation factors with roman numeral was agreed upon at various congresses. Consensus was reached on the naming of factors I to XII by 1962 and assignment of numerals ceased in 1963 with the addition of factor XIII.
Factor VI was found to be Va (accelerin) and is now unassigned.
| Clotting factor common name | Synonym |
|---|---|
| Fibrinogen | I |
| Prothrombin | II |
| Tissue factor | III |
| IV | Calcium |
| V | Proaccelerin |
| (unassigned) | |
| VII | Proconvertin |
| VIII | Antihaemophilic factor (A) |
| iX | Christmas factor |
| X | Stuart-Prower factor |
| XI | Plasma thromboplastin antecedent |
| XII | Hageman factor |
| XIII | Fibrin stabilising factor |
| Prekalikrein | Fletcher factor |
| High-molecular-weight kininogen | Fitzgerald factor |