Haemostasis

Question 1

Haemostasis tests performed by side of the animal

Answer 1

1) Capillary resistance
2) BT, BMBT
3) Appearance of the first fibrin strand
4) Appearance of the clot
5) Clot retraction time

Question 2

Normal BMBT.

Answer 2

3-5 min

Question 3

Sample for coagulation time

Answer 3

Fresh blood without anticoagulants

Question 4

Normal time for appearance of first fibrin strand.

Answer 4

1-2 min

Question 5

Normal clotting time of watch glass

Answer 5

7-15 min

Question 6

Normal clotting time in plastic syringe

Answer 6

10-12 min

Question 7

Normal clotting time in a glass test tube

Answer 7

4-5 min

Question 8

Normal clotting time in activated clotting time (ACT) tube.

Answer 8

3 min

Question 9

Sample for platelet (thrombocyte) count.

Answer 9

Na2- or K2-EDTA anticoagulated blood.

Question 10

Normal platelet count

Answer 10

200-800 x 10^9/L

Question 11

Normal clot retraction time

Answer 11

1 hour: the volume of serum released is 25 % of the volume of the initial clot.

Question 12

Tests for vasopathies

Answer 12

• Capillary resistance

- BT, BMBT

Question 13

Tests for thrombocytopathies

Answer 13

• BT, BMBT
• Platelet count
• Clot retraction test
• Platelet aggregation test

Question 14

Tests for thrombocytopaenia

Answer 14

• BT, BMBT

- Platelet count

Question 15

Platelet size of horses, sheep and cattle.

Answer 15

3-5 fl

Smallest

Question 16

Platelet size of dogs and swine

Answer 16

7-8 fl

Question 17

Platelet size of cats.

Answer 17

10-15 fl

biggest

Question 18

Normal prothrombin (PT) time

Answer 18

10-15 sec

Question 19

Normal activated prothrombin time (APTT)

Answer 19

20-30 sec

Question 20

Major causes of thrombocytopaenia.

Answer 20

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.

Question 21

What is the name of the contractile protein responsible for clot retraction?

Answer 21

Thrombostenin

Question 22

Major causes of thrombocytopathies.

Answer 22

1) Improper platelet development. (i.e. hereditary glycoproteins deficiency)
2) Von Willebrand’s disease.
3) uraemia
4) liver failure
5) lymphoproliferative diseases
6) NSAIDs

Question 23

Major causes of coagulopathies of the intrinsic pathway.

Answer 23

1) Haemophilia A factor VIII deficiency
2) Haemophilia B factor IX deficiency
3) Von Willebrand’s disease

Question 24

Major causes of coagulopathies of the extrinsic pathway.

Answer 24

1) Factor VII deficiency

2) first stage of dicumarol toxicosis

Question 25

Major causes of coagulopathies of the common pathway.

Answer 25

1) Liver disease (decreased production of coagulation factors) 2) DIC 3) Second stage of dicumarol toxicosis 4) Factor X, V, II, I, XIII deficiency

Question 26

What sample should be used for thrombocyte counting?

Answer 26

Na2- or K2- EDTA anticoagulated blood.