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Name each blood coagulation factor including all names
- I Fibrinogen
- II Prothrombin
- III Tissue Thromboplastin, Tissue factor
- IV Ionized Calcium
- V Labile factor, proaccelerin
- VI
- VII Stable factor, serum prothrombin conversion accelerator (SPCA), proconvertin
- VIII Antihemophilic factor A
- VIII:C or VIII:AHF coagulant portion
- VIII:vWF von Willebrand portion
- IX Christmas factor, plasma thromboplastin component (PTC), antihemophilic factor B
- X Stuart-Prower factor
- XI Plasma thromboplastin antecedent (PTA)
- XII Hageman factor, contact factor
- XIII Fibrin stabilizing factor (FSF)
- HMWK Fitzgerald factor, High-molecular-weigh-kininogen (HMWK)
- PK Fletcher factor, Prekallikrein (PK)
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List the blood coagulation factors grouped by function
- Substrate: Factor I
- Cofactors: Factors V and VIII:C(AHF)
- Enzymes; Proteases: activated forms of II, VII, IX, X, XI, XII, PK
- Enzymes; Transaminase: activated form of XIII
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List the blood coagulation factors grouped by physical properties w/ info about grouping
- Fibrinogen group: I, V, VIII, XIII
- high MW proteins
- also found in platelets
- acted on by thrombin
- consumed during coagulation
- NOT vitamin K dependent for synthesis
- Prothrombin group: II, VII, IX, X
- low MW proteins
- contain gamma carboxyglutamic acid
- not consumed during coagulation (except II)
- vitamin K dependent for synthesis
- Contact group: XI, XII, PK, HMWK
- involved in initial phase of intrinsic system activation
- not consumed during coagulation
- not Vitamin-K dependent for synthesis
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Describe the Extrinsic pathway in words
- (VII)
- Injury occurs, fluid containing III (tissue factor) enters blood stream
- III + Ca activates VII
- VIIa and III activate the common pathway (X) and the intrinsic pathway
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Describe the Intrinsic pathway in words
- (VIII, IX, XI, XII)
- XII comes in contact with collagen and is activated
- XIIa + HMWK + PK activate XI
- Ca + XIa activate IX
- PF 3 + VIII:C + Ca activate + IXa activate X (the common pathway)
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What is the tenase complex in the intrinsic and extrinsic pathways?
- Intrinsic: IXa + Ca + PF 3 + Factor VIII:C
- Extrinsic: VIIa + Ca + III
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Describe the common pathway in words
- (I, II, V, X)
- Tenase activates X
- Xa + Ca + PF 3 + V activates II
- IIa activates XIII AND I
- I forms fibrin monomer
- XIIIa + Ca form fibrin polymer (then fibrin clot)
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Describe thrombin's action on fibrinogen and the stabilization of a clot
- Fibrinogen consists of alpha, beta, and gamma chains
- Thrombin cleaves the alpha and beta chains of firbinogen resulting in a fibrin monomer + fibrino peptides A and B
- Spontaneous polymerization of fibrin occurs (weak H bonds)
- XIIIa and Ca stabilize the clot (cross-linked fibrin polymer)
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What tube is normally used for factor testing?
NaCitrate (lt blue) within 2 hours
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What are the screening tests for hemostasis disorders w/ brief description
- Platelet count
- Bleeding time: std pressure + stick... how much time to stop bleeding?
- Prothrombin time: tests for Extrinsic and common pathway (I, II, V, VII, X)
- uses thromboplastin-calcium reagant
- normal is 11-13s
- Activated partial thromboplastin time: tests intrinsic and common pathways (I, II, V, VIII, IX, X, XI, XII)
- uses partial thromboplastin (PF 3 substitute) and Ca reagant
- normal is <35s
- Thrombin time: tests conversion of fibrinogen to fibrin
- uses thrombin reagant, no calcium
- normal is 10-15s (15-22s)
- Quantitative fibrinogen assay: tests conversion of fibrinogen to fibrin
- normal is 200-400mg/dL
- Evaluation of factor XIII: tests factor XIII activity
- form plasma clot with thrombin
- observe fibrin stabilized clot in 5M urea over time
- will disseminate quickly if factor XIII issue
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Describe the acquired blood coagulation defects
- Vitamin K deficiency: hemorrhagic disease of newborn, liver disease, oral anticoagulants (coumadin)
- Heparin therapy: antithrombin
- Acute disseminated intravascular clotting (DIC): massive injury releases too much III and clotting factors are used up
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Describe the hereditary blood coagulation defects
- Classical hemophilia A: VIII:C deficiency
- joint bleeding leading to swelling
- von Willebrand's disease: VIII:vWF deficiency
- bruising
- hemophilia B (christmas disease): IX deficiency
- Rare deficiencies: I, II, V, VII, X, XII
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Describe the fibrinolytic pathway
- P. activator and Tissue P. activator activate plasminogen
- Plasmin cleaves fibrinogen into FDP (fibrin degredation products) which can be measured
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Describe the laboratory evaluation of fibrinolysis
- Latex particles are coated with antibodies to the D and E fragments of FDPs
- D and E fragments cause particles to clump
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Describe the defects of fibrinolytic activity
- Primary fibrinolysis: results in fibrin/fibrinogen split products (FSP), decreased V and VIII:C
- Etiology: massive strep infections producing streptokinases
- kidney cancers producing urokinases
- trauma (crush) incidents
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