Haemostasis Flashcards
Haemostasis tests performed by side of the animal
1) Capillary resistance
2) BT, BMBT
3) Appearance of the first fibrin strand
4) Appearance of the clot
5) Clot retraction time
Normal BMBT.
3-5 min
Sample for coagulation time
Fresh blood without anticoagulants
Normal time for appearance of first fibrin strand.
1-2 min
Normal clotting time of watch glass
7-15 min
Normal clotting time in plastic syringe
10-12 min
Normal clotting time in a glass test tube
4-5 min
Normal clotting time in activated clotting time (ACT) tube.
3 min
Sample for platelet (thrombocyte) count.
Na2- or K2-EDTA anticoagulated blood.
Normal platelet count
200-800 x 10^9/L
Normal clot retraction time
1 hour: the volume of serum released is 25 % of the volume of the initial clot.
Tests for vasopathies
- Capillary resistance
- BT, BMBT
Tests for thrombocytopathies
- BT, BMBT
- Platelet count
- Clot retraction test
- Platelet aggregation test
Tests for thrombocytopaenia
- BT, BMBT
- Platelet count
Platelet size of horses, sheep and cattle.
3-5 fl
Smallest
Platelet size of dogs and swine
7-8 fl
Platelet size of cats.
10-15 fl
biggest
Normal prothrombin (PT) time
10-15 sec
Normal activated prothrombin time (APTT)
20-30 sec
Major causes of thrombocytopaenia.
1) Decreased production of thrombocytes in the bone marrow.
2) Increased utilisation: DIC
3) Increased destruction: autoimmune thrombocytopaenia.
4) Increased sequestration: splenomegaly.
5) Increased loss: subacute/chronic bleeding.
What is the name of the contractile protein responsible for clot retraction?
Thrombostenin
Major causes of thrombocytopathies.
1) Improper platelet development. (i.e. hereditary glycoproteins deficiency)
2) Von Willebrand’s disease.
3) uraemia
4) liver failure
5) lymphoproliferative diseases
6) NSAIDs
Major causes of coagulopathies of the intrinsic pathway.
1) Haemophilia A factor VIII deficiency
2) Haemophilia B factor IX deficiency
3) Von Willebrand’s disease
Major causes of coagulopathies of the extrinsic pathway.
1) Factor VII deficiency
2) first stage of dicumarol toxicosis
Major causes of coagulopathies of the common pathway.
1) Liver disease (decreased production of coagulation factors)
2) DIC
3) Second stage of dicumarol toxicosis
4) Factor X, V, II, I, XIII deficiency
What sample should be used for thrombocyte counting?
Na2- or K2- EDTA anticoagulated blood.
