Coagulation Flashcards
Extrinsic pathway
PT
Intrinsic pathway
aPTT
Common Pathway
PT + aPTT
Fibrinogen -> fibrin (after thrombin has been added)
The thrombin time (TT), also known as the thrombin clotting time (TCT), is a blood test that measures the time it takes for a fibrin clot to form in the plasma of a blood sample.
INR (normal)
1.0
aPTT - long
PT, TCT - normal
Intrinsic pathway defects
Factor VIII
Factor IX
contact def - factor IX
factor XII
PT - long
aPTT, TCT - normal
Extrinsic factor defects
Factor VII deficiency
TCT - long
aPTT, Pt - normal
Fibrinogen defects
- mild to moderate fibrinogen deficiency
- low conc of fibrinogen inhibitors
aPTT, PT - long
TCT - normal
Common pathway affected
- factor II
- Factor V
- FActor X
combined def -
vit K dependant factors - II, VII, IX, X (2, 7, 9, 10)
All - long
Fibrinogen
- severe deficiency
- high conc of inhibitors
combined def -
- def of fibrinogen, intrinsic, extrinsic and common pathway factors
- PT, aPTT - long
- declining platelet count
- Fibrinogen (acute phase reactant) - low or normal (slightly elevated)
- increased fibrin degrading products - D-dimers
- low antithrombin III levels
- schistocytes in peripheral blood smear
DIC
DIC
- PT, aPTT - long
- declining platelet count
- Fibrinogen (acute phase reactant) - low or normal (slightly elevated)
- increased fibrin degrading products - D-dimers
- low antithrombin III levels
- schistocytes in peripheral blood smear
von Willebrand disease
a common inherited condition that can make you bleed more easily than normal.
People with VWD have a low level of a substance called von Willebrand factor in their blood, or it does not work very well.
Von Willebrand factor helps blood cells stick together (clot) when you bleed.
- patients rarely bleed into joints
- report bruising
Vitamin-k dependant coagulation factors
II, VII, IX, X
2, 7, 9, 10
Common pathway factors
The common pathway factors X, V, II, I, and XIII
10, 5, 2, 1 and 13
[(10+5) - 2] x 1= 13
Intrinsic pathway factors
factors XII, XI, IX, and VIII
12, 11, 9 and 8
Extrinsic pathway factors
I, II, VII, and X
INR - normal and on warfarin
n healthy people an INR of 1.1 or below is considered normal. An INR range of 2.0 to 3.0 is generally an effective therapeutic range for people taking warfarin for disorders such as atrial fibrillation or a blood clot in the leg or lung.
