Haemolysis Flashcards
What is Bleeding time?
Measure of the time from the appearance of the first drop of blood until the cessation of bleeding.
What tests can you use for coagulation time and how do you carry them out?
Clotting time on a watch glass, Clotting time in plastic syringe, Clotting time in activated clotting time tube
What is coagulation in an ACT test tube?
Si02 with fresh blood to check the coagulation without the contact factor (Hagemann factor) at 37c.
How long does each test take to coagulate?
3 minutes is normal
What are the causes of thrombocytopenia?
Decrecreased production of thrombocytes in the bone marrow, increased utilization of thrombocytes, (DIC), increased destruction of thrombocytes automimmune thrombocytopenia (AITP), increased sequestration of thrombocytes
Which factors are dependent on vitamin K?
Proconvertin (Factor 7), Christmas (Factor 9), Stuart Prower (Factor 10), and Prothrombin (Factor 2)
What is prothrombin time?
Gives information about the function of the extrinsic pathway because the coagulation cascade is triggered by adding tissue factor.
How long is a normal PT?
10-15 seconds
What is APTT?
Activated partial thromboplastin time – gives information on the function of the intrinsic pathway through the provision of surface activation
How long is a normal APTT?
How long is a normal APTT?
20-30 seconds
What is the general platelet count?
200-800 x 10 to the 9
What is DIC?
Disseminated intravascular coagulopathy. Secondary problem where microthrombus formation and fibrinolysis are present at many different places in the body simultaneously because of severe tissue damage or necrosis
Something about Von Willebrands disease, basically wanted to know which clotting factor was messed up.
Factor VIII is deficient
What are the major groups of haemostasis disorders?
Vasculopathy, Thrombocytopathy, Coagulopathy
What tests were used to investigate coagulopathies?
Bleeding time, (buccal mucosal bleeding time test,) clotting time, clotting time on different
surfaces, clot retraction time.
What tests investigate platelet count (can’t remember the exact phrasing of her question there but its
pretty much what she wanted.)
blood smear test, automatic cell counters, Burker chamber count
What is the clot retraction test?
The measure of the decrease in clot size with a contractile protein called thrombostenin. Slower or
no contraction happening is a sign of thrombocytopathy
In dicumarol posioning what is increased?
The PT and APTT is increased
what was increased in Haemophilia type A
???
How can you count platelets in a sample
Burker chamber (haemocytometer), blood smear, automatic cell counters.
Which hemostatic disorder lead to more sever clinical signs, thrombocytpathys or coagulopathys?
Thrombocytopathy as there is no connection between thrombocyte-thrombus
Shortest coagulation factor life time?
(7) 3 minutes with the CT in ACT
Which factor is involved in measuring thrombin time
(13??)
Time until the first fibrin strain
1-2 minutes
What does silicon dioxide influence in ACT
The contact factor Hagemann factor
How does dicoumarol anticoagulant work
It is the competitive antagonist of vitamin k which is responsible for the gamma carboxylation of
proconvertin(Factor 7) Christmas factor (Factor 9), Stuart Prower (Factor 10) and he Prothrombin
(Factor 2). It removes Ca2+ from these factors so they cannot activate
Clot retraction test
Measure of the effectiveness of thrombostenin for reducing the clot via the release of serum.
Platelet count normal number
200-800 x 10 to the 9
Platelet count formula for smear (20*10^9/l)
Which anticoagulant used for platelet count examination
EDTA, K2, Na2-
Dicumarol toxicosis effect on PT an APTT
Increases quickly on PT then gradually on APTT
Ratio of anticoagulant (citrate:blood)
1:9
Thrombocytopenia, name 3 causes
Decreased production of thrombocytes in the bone marrow, increased utilization of thrombocytes
DIC (disseminated intravascular coagulopathy), increased loss of thrombocytes: subacute/chronic
bleeding
How does sodium citrate inhibit coagulation
Citrate prevents coagulation by binding calcium ions
DIC
Disseminated intravascular coagulopathy (DIC) microthrombus formation and fibrinolysis are
present at many different locations in the body due to necrosis or severe tissue damage.
BMBT time
3-5 minutes
How is BMBT performed
0.5 cm incision on the skin of the inner part of the external ear or the buccal mucosal surface. Wipe
away excess blood under the incision until the cessation of bleeding
What level of platelets are considered a clinical bleeding disorder
Above 50x10 to the 9/Liter
Function of platelets
They bind thrombocytes along with fibrin to form clots in damaged blood vessels
What do factors need for their synthesis
Calcium ion
Which factor is 13 and what is its function
Von Willebrand Factor is responsible for plately adhesion and aggregation and anti haemophylic
factor.
What factor are in extrinsic pathway
3, 7, 5, 10, 2, 13
Which factors can bind to Calcium
Proconvertin (Factor 7), Christmas (Factor 9), stuart prower (Factor 10), Prothrombin (Factor 2)
What molecule can activate factor 12 (hagemann)
Free collagen fibres, kininogen, and kallikrein
What is the glue that sticks the thrombocytes to each other
Polymerized fibrin network
What factor initiates the intrinsic pathway
Hagemann factor Factor 12
What factor is calcium
Factor 4
