Hemostasis II Flashcards
1
Q
At whatplatelet count is there prolonged bleeding after trauma?
A
< 50,000per uL
2
Q
At what platelet count is there increased risk of spontaneous bleeding?
A
< 20,000 per uL
3
Q
What is the diagnostic value of bleeding time (BT)?
A
- Very high sensitivity in vWF disease, low sensitivity for platelet aggregation disorders.
- Specificity is low
4
Q
What lab tests check fibrin clotformation?
A
- Prothrombin time (PT)
- INR
- Partial thromboplastin time (PTT)
- Thrombin time (TT)
5
Q
What does PTT and PT check for?
A
6
Q
Explain PT test.
A
Prothrombin Time
- Detects defects in extrinsic and common pathway – I, II, V, VII, X • Some causes of an abnormal test
- liver disease
- vitamin K deficiency
- warfarin
7
Q
How do we measure INR?
A
8
Q
Explain PTT test.
A
Partial Thromboplastin Time
- Detects defects in intrinsic and common pathway – I, II, V, VIII, IX, X, XI, XII, HMWK, PK Some causes of an abnormal test
- hemophilia A and B
- von Willebrand disease
- heparin therapy
- liver disease (if severe)
- vitamin K deficiency (if severe)
- warfarin (if supra-therapeutic)
9
Q
Explain TT test.
A
10
Q
How do we measure for total rate of fibrinolysis in a patient?What is its sensitivity and specificity?
A
Via D dimer test, remember plasmin breaks down the clotby excising the bond between E and D subunits of fibrin polymer, resulting in the formation of D-dimers.D dimer test uses ELISA, it has very high sensitivity for DIC.
