Card Set Information
Lab Tech ll
Lab Tech ll
List the parts of the normal hemostatic mechanism.
: vessel wall & thrombocytes
: coagulation factors form fibrin
: plamin dissolves fibrin
List 5 different mechanisms by which hemostatic disorders can be produced.
hemophilia A & B
von Willebrand's disease
List 6 different clinical signs associated with hemostatic disorders.
petechiae & ecchymosis
bleeding into sub q, muscles, and joints
Which anticoagulant is used for coagulation factor tests?
cell in bone marrow that thrombocytes break off of
Define activated clotting time.
tests intrinsic/common pathways (secondary hemstasis)
clots occuring intravascularly all over the body.
digestive blood in poop
Name 3 inherited hemostatic disorders.
Name 4 diseases often associated with hemostatic disorders.
List three pathophysiologic mechanisms by with a thrombocytopenia may be produced.
List three different tests which may be run on the SCA 2000.
What is hemostasis?
a protective mechanism
prevents blood loss due to minor injury
protects against disorders that cause bleeding
What is thrombocytopathy?
disease of thrombocytes not functioning correctly
What is thrombocytopenia?
decrease in the normal amount of thrombocytes
What does DIC stand for?
dissemenated intravascular coagulation
What happens when there is injury to the vessel wall?
vasoconstriction occurs within seconds which stimulates the release of factor III
How long does vasoconstriction last when there is injury to the vessel wall?
lasts less than 1 minute
Are vasculopathies rare?
Where are thrombocytes produced?
in bone marrow
What do thrombocytes adhere to?
subendothelial collagen of vessel walls
What do thrombocytes release?
What do thrombocytes stimulate?
second degree of hemostasis
Where are clotting factor produced?
in the liver
Which clotting factor is not produced in the liver?
How many clotting factors are there?
What do clotting factors function as?
enzymes activating on another
Do we need all 12 clotting factors to get fibrin?
What happens if we do not have all 12 clotting factors?
unstable clot that will cause bleeding again
What are the three different chemical reactions in clotting factors?
What is the end result of the clotting factors pathway?
What does fibrin do?
stabilizes platelet plug
What does anticoagulants do? What does EDTA specifically act on? Heparin?
act on clotting factors to prevent clotting
EDTA removes calcium from the blood
Heparin prevents prothrombin from converting to thrombine
What are the clotting factors in the extrinsic pathway?
What are the clotting factors in the intrinsic pathway?
factors XII, XI, IX, VIII, VI, Ca
What are the clotting factors in the common pathway?
Factors X, V, IV, III, II, I
Which clotting factor is the most important in the extrinsic pathway? What is it specifically?
What is factor I?
Where are the intrinsic pathways?
all within the vessel
already found in blood
How is the extrinsic pathway activated?
tissue factor III activated by tissue injury
What is needed to make factor VII?
What is the common pathway?
where intrinsic and extrinsic pathways come together
In the common pathway, X, V, and calcium activate what? What does the reaction do?
X, V, and calcium activate factor II
prothrombin turns to thrombin
Factor II activate what? What does this reaction do?
factor II activates factor I
fibrinogen turns to fibrin
What are the signs and defects of secondary hemostasis?
bruises and hematomas
bleeding into sub q, muscles, and joints
When does fibrinolysis occur?
after the clot has formed
In fibrinolysis, plasminogen is converted to what?
Plasmin are fragments of what?
Where is fibrin removed?
by the liver
Is a detailed history from the owner important when diagnosing hemostatic disorders?
What can hemostatic signs be due to?
When do we do screening tests for a hemostatic disorder?
when we suspect a clot disorder
What kind of controls can we use when doing screening tests for hemostatic disorders?
normal animals in the hospital
How many platelets are normal in an oil field?
8 - 10
What will make the platelet count appear low?
When should we do a direct thrombocyte count?
within 4 hours of collecting the blood or they will disappear
Which species thrombocyte count is usually inaccurate when using an automated counter?
At what platelet count do we usually see signs of hemostatic disorders?
What are the mechanisms of thrombocytopenia? And what causes each one?
: drugs, anaplasma platys, FeLV
: immune mediated, modified live virus, drugs
: DIC, splenic torsion, sepsis
What is sepsis?
local or generalized invasion of the body by pathogenic microorganisms or their toxins
How do we check thrombocyte morphology?
check a blood smear
What do we look for in thrombocyte morphology?
What causes large platelets?
megakaryocytic hyperplasia (young platelets)
a regenerative response
What are schistocytes?
When do we usually see schistocytes?
in DIC or vascular neoplasia
What is cyclic thrombocytopenia?
thrombocytopenia that comes and goes
What are the different tests we can do for hemostatic disorders?
activated clotting time
partial thromboplastin time (PTT)
prothrombin time (PT)
blood coagulation analyzers
What kind of blade do we use for the bleeding time test?
When is the bleeding test over?
when a clot forms
How do we do the buccal mucosal bleeding test?
cut a hairless area (gums work best)
gentle blotting with no pressure
note time until clot forms
What are the normal times for a clot to form in a dog? Cat?
: 1.7 - 4.2 min
: 1.4 - 2.4 min
What does bleeding time evaluate?
The most common reason we see a bleeding defect is due to _____. Most common type of _____ is _____.
If there is a prolonged bleeding time then we know we have a problem with what?
What is clot retraction?
crude test of platelet function
How do we do a clot retraction test?
leave blood in a tube without anticoagulant
clot should retract from the wall of the tube within 1 hour
we consider it a problem if it takes more than 24 hours - suggests platelet malfunction
How do we do an activated clotting time test?
must use a vaccutainer
avoid the first few drops of blood
fill a 2ml ACT tube
warm the tube and blood to body temperature
leave in the warmer for 50 second, and invert every 10 seconds
note the time the blood clots
What is in the ACT tube?
diatomaceous earth...dinosaurs :(
How long should it take a dogs blood to clot during the activated clotting time test? Cats?
: 60 - 110 seconds
: 50 - 75 seconds
If an animal has thrombocytopenia what will happen during the activated clotting time test?
will automatically be prolonged giving us false results
What does partial thromboplastin time test?
Which test is more sensitive, PTT or ACT?
What does PTT stand for?
partial thromboplastin time
What time of plasma must we use for the PTT test and what tube do we use to get it?
blue top tube (sodium citrate)
What is PTT used to diagnose?
Do we need to fill the sodium citrate tube completely when running the PTT test? Why or why not?
must have the appropriate ratio of blood to sodium citrate
When should we run the PTT test?
within 3-4 hours of collecting the blood
What does the prothrombin time test for?
tests for factor VII
What does PT stand for?
What kind of plasma is needed to run PT test?
When should we run the PT test?
within 2 hours of collecting blood
What does PT mostly diagnose?
coumarin toxicity and DIC
What are the most common blood coagulation analyzers?
COAG Dx (formally SCA 2000)
VS Pro (Abaxis)
What kind of test does the COAG DX (SCA 2000) run?
What does the COAG Dx (SCA 2000) evaulate?
evaluates intrinsic, extrinsic, and common pathways
What kind of tests does the VS Pro (Abaxis) run?
What is von Willebrand's disease?
an inherited bleeding disorder
deficiency of vW factor
What is the vW factor?
chemical that facilitates platelets attaching
What does the vW factor carry?
von Willebrand's disease has a deficiency of what?
How do we test for vWf (vW factor)?
send out citrated plasma
separate immediately, freeze quickly
Are there genetic tests available for von Willebrand's disease?
What is DIC?
massive stimulation of clotting mechanisms
What are some clinical signs of DIC?
What is usually the outcome of DIC?
death usually occurs
What are some common causes of DIC?
How do we diagnose DIC?
initiating condition present
bleeding/organ failure (petechiae/ecchymoses)
all coagulation tests are prolonged
What is hemophilia?
unable to clot blood
What are the two types of hemophilia?
Is hemophilia inherited?
yes, sex linked
Which chromosome is hemophilia carried on?
What type of deficiency does hemophilia A have?
What type of deficiency does hemophilia B have?
What test is prolonged when we have a patient with hemophilia?
What is coumarin toxicity?
What does coumarin block?
What factor does coumarin toxicity lack?
How is coumarin toxicity diagnosed?
prothrombin time is prolonged
Which tests are normal with coumarin toxicity?
What is in rodenticides that causes the calicum in an animal to increase?
What are vascular disorders?
disease of vessels
What type of diseases are vascular disorders?
How are vascular disorders diagnosed?
eliminating other possibilities