Clinical Coag Final Flashcards
What causes a prolonged bleeding time due to its effect on platelet aggregation?
aspirin
What depends on the conversion of plasminogen in the plasma to the active form plasmin?
fibrinolysis
What is a test for fibrinolysis?
clot lysis
What is a more rapid test to detect increased clot lysis?
euglobin lysis time
What is Stage I of coagulation?
the formation of plasma thromboplastin
What is Stage II of coagulation?
conversion of prothrombin to thrombin
What is Stage III of coagulation?
conversion of fibrinogen to fibrin
What is thrombasthenia?
normal number and abnormal function of platelets
What is thrombocytopenia?
decreased and normal function of platelets
What is thrombocythemia?
increased and abnormal function of platelets
What is telangiectasia?
hereditary vascular abnormality
What is thrombocytosis?
increased and normal function of platelets
What is the only factory deficiency that causes a prolonged thrombin time?
Fibrinogen (Factor I)
What factors cause an increased PT?
VII, X, V, II, I
What factors cause an increased PTT?
XII, XI, IX, VIII
What factors cause an increased PT and PTT?
X, V, II, I
Factor deficiencies involving labile factors must be treated with what?
fresh blood or FFP
What are the labile factors?
V and VIII
How is Hemophilia A and vonWillebrand’s disease distinguished?
bleeding time
What factor deficiency is seen in both Hemophilia A and vonWillebrand’s disease?
Factor VIII
What will correct a PT due to Factor VII deficiency?
Russell’s viper venom (Stypven)
What is the initial plug in the wall of a vessel composed of?
platelets
What replaces platelets in the plug in the wall of a vessel?
fibrin
What Factor is required for the intrinsic system of coagulation?
Platelet Factor 3
What is the normal platelet count?
150000-400000
Bleeding does not usually occur unless the platelet count falls below what?
50,000
What form of bleeding occurs most often when the platelet count falls below 50,000?
petechiae and ecchymoses
What is the preferred anticoagulant for the PT and PTT?
sodium citrate
What is the ratio of blood to anticoagulant in a sodium citrate tube required for a PT and PTT?
9 to 1
What are the liver factors?
I, II, V, VII, IX, XIII
What are the Vitamin K dependent factors?
II, VII, IX, X
What are the adsorbed plasma factors?
V, VIII, XI, XII
What are the aged serum factors?
VII, IX, X, XI, XII
What is used to monitor the intrinsic pathway and heparin therapy?
PTT
Normal values for the Duke method for bleeding time
1-3 minutes
Normal values for the Ivy method for bleeding time
1-6 minutes
Normal value for the template method for bleeding time
2.3-9.5 minutes
What is the more rapid test to detect increased clot lysis?
euglobulin lysis time
How much time is required to perform the euglobulin lysis time?
2 hours
In interpreting fibrin split products, agglutination in neither the 1:5 or the 1:20 indicates
In interpreting fibrin split products, agglutination in 1:5 but not in 1:20 indicates
> 10 mcg/mL
In interpreting fibrin split products, agglutination in 1:5 and 1:20 indicates
> 40 mcg/mL
What is the best test to distinguish between primary and secondary fibrinolysis?
platelet count, greatly decreased in secondary
What is Stave IV of coagulation?
fibrinolysis
What are the best tests to screen for coagulation disorders?
PT and PTT
PT is used to monitor what?
Intrinsic pathway and heparin
PTT is used to monitor what?
extrinsic pathway and coumadin
What tests, other than PT, can be used to monitor heparin?
Lee White clotting time and Thrombin Time
What is the only test for Factor XIII?
5M urea solubility test
What initiates the extrinsic system of coagulation?
tissue factor III
What initiates the intrinsic system of coagulation?
exposed collagen, activation of contact factor, or by platelet factor 3
What factor is the contact factor?
Factor XII
How does coumadin act?
Interferes with the synthesis of the Vitamin K dependent factors
How does heparin act?
works with antithrombin III to neutralize thrombin
What is the antidote for heparin?
protamine sulfate
What is the principle of the fibrometer?
completes and electrical circuit between the two electrodes by the formation of a clot
What is the principle of the coagulyzer, Coag-A-mate, and MLA?
detection of optical density changes in a cute by the photocell when the clot is formed
What clotting factors have an enzymatically active form
II, VII, IX, X, XI, XII, and XIII
What is the use of substitution testing with adsorbed plasma and aged serum?
pinpoints factor deficiencies
How should the overall competence of the coagulation system be tested?
PT, PTT, bleeding time, clot solubility test, and a fibrinogen level