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CHAPTER 27 ■ Principles of Hemostasis and Thrombosis: Blood Coagulation Factors and Natural Coagulant Systems 527

He atic ce s are the rinci a site o the synthesis o Common Characteristics of Coagulation

coagu ation actors. However, other ce s, such as en othe ia Factors

ce s, a so ay an i ortant ro e in the nor a rocess o

he ostasis an thro bosis. C assica y, the coagu ation ac- Proteins that are c otting actors have our characteristics in

tors have been escribe as reacting in a casca ing sequence. co on. T ese characteristics are as o ows:

Mo i cations o this sequence are now known to occur as 1. A e ciency o the actor genera y ro uces a b ee ing

the b oo actors interact to or the na inso ub e ge ati- ten ency isor er with the exce tion o actor XII, reka -

nous thro bus. ikrein (F etcher actor), an high– o ecu ar weight

kininogen (HMWK; Fitzgera actor).
Basic Concepts of Blood Coagulation 2. T e hysica an che ica characteristics o the actor are

known.
B oo coagu ation is a sequentia rocess o che ica reac- 3. he synthesis o the actor is in e en ent o other

tions invo ving as a roteins, hos ho i i s, an ca - roteins.

ciu ions. Most o the circu ating actors ( ab e 27.1) that 4. T e actor can be assaye in the aboratory.

artici ate in the coagu ation rocess are esignate by

Ro an nu era s. T e activate or o an enzy atic ac- o eve o an un erstan ing o the theory o coagu ation

tor a ears as a Ro an nu era o owe by the su x -a, an the un er ying rinci es o re ate aboratory roce-

whereas the inactive enzy atic actors, are in icate by the ures, it is he u to co are the characteristics ( ab e 27.2)

Ro an nu era a one. For exa e, actor II, rothro - o various coagu ation actors. T ree grou s o actors exist:

bin, is esignate as actor II; however, in the active state, the brinogen grou , the rothro bin grou , an the con-

it is IIa, thro bin. Nonenzy atic actors have no such tact grou .

esignations. T e Ro an nu era esignation oes not Te brinogen group consists o actors I, V, VIII, an XIII.

in icate the sequence o reactions in the c otting rocess. T ese actors are consu e uring the rocess o coagu a-

For exa e, actor X rece es actor II in the coagu ation tion. Factors V an VIII are known to ecrease uring b oo

athway. storage in vitro. T ese actors are known to increase uring

TABLE 27.1 Proteins in Blood Coagulation

Factor Name Alternate Terms

Coagulation Factors

I Fibrinogen

II Prothrombin

V Proaccelerin Labile factor, Ac globulin

VII Proconvertin Stabile factor, SPCA

VIII AHF AHG, antihemophilic factor A

IX PTC Christmas factor, antihemophilic factor B

X Stuart factor Stuart-Prower factor

XI Plasma thromboplastin antecedent PTA, antihemophilic factor C

XII Hageman factor Glass or contact factor

XIII Fibrin-stabilizing factor FSF

Others Prekallikrein Fletcher’s factor

HMW kininogen HMW kininogen, Fitzgerald’s factor

vWF Factor VIII–related antigen

Fibronectin

Antithrombin

Heparin cofactor II

Protein C

Protein S

SPCA, serum prothrombin conversion accelerator; AHF, antihemophilic factor; AHG, antihemophilic globulin; PTC, plasma thromboplastin component; PTA,

plasma thromboplastin antecedent, FSF, brin-stabilizing factor; HMW, high–molecular weight kininogen; vWF, von Willebrand factor.