Coag Study Guide Flashcards
What is the normal value for Duke bleeding time?
1-3 minutes - earlobe
What is the normal value for Ivy bleeding time?
less than 10 minutes - forearm
What is the normal value for the template bleeding time?
standard, outdated. ASK
Aspiring causes a prolonged bleeding time due to ?
inhibits platelet aggregation
Interpret results on Thrombo Wellco agglutination test
10 40 mcg/mL
1:20
Fibrinolysis depends upon the conversion on ? in the plasma to the active form of ?
plasminogen
plasmin
Clot lysis is a test for ? and takes ? hours
Fibrinolysis
72
A more rapid clot test for lyisis is ? and takes ? hours
euglobulin
2
Primary fibrinolysis is difficult to distinguish from secondary because?
Primary usually decreased but still in normal range
Secondary (DIC) greatly decreased because they are consumed by clotting
PBS in primary and secondary
Primary - normal
Secondary - schistocytes due to effect of clotting on rbc/s
Four stages of coagulation
formation of thromboplastin
conversion of prothrombin to thrombin
conversion of fibrinogen to fibrin
fibrinloysis due to thrombin
Why are the PT and PTT good choices for coag testing?
Simple
relatively short time
tests for all factors
share one tube
Besides PT and PTT, what test is a good choice for coag testing?
Bleeding time
quick and checks platelet function
Why is the clotting time test not a good choice for coag test?
inconvenient
drawn with syringe
performed immediately
What vascular disorder is related to thrombasthenia
normal, abnormal function
What vascular disorder is related to thrombocytopenia?
decreased, normal function
What vascular disorder is related to thrombocythemia?
increased, abnormal function
What vascular disorder is related to telangiectasia?
Hereditary vascular abnormality
What vascular disorder is related to thrombocytosis?
increased, normal function
What factor deficiency causes a prolonged thrombin time
Fibrinogen (I)
What factors increase PT?
I II V VII X
What factors increase PTT?
VIII IX XI X V II I
Which factors increase both PT and PTT?
I
II
V
X
Which are labile factors and how are deficiencies treated?
V
VIII
fresh blood or FFP
Which test is performed to differentiate vWD from Hemophilia A
Bleeding time- both involve VIII deficiency
PT - increased but vWD has plt abnormality
What will correct a PT due to deficiency of Factor VII
Russell’s Viper Venom (stypven)
What is the initial plug on the wall of a vessel comprised of initially and then replaced by
platelets replaced by fibrin
Patelet Factor 3 is required for which system of coagulation
Intrinsic
source of phospholipid
What is the normal platelet count
150,000-400,000
At what plt count will bleeding occur
below 50,000
usually in form of petechiae and scchymoses
Anticoagulant for PT and PTT
sodium citrate
Ratio of blood to anticoagulant in PT and PTT
9:1
low Hct - too much anticoag
high Hct - needs More anticoag
Liver Factors
I II V VII IX X
Vitamin K dependent
II
VII
IX
X
Absorped plasma factors
V
VIII
IX
X
Aged serum
VII IX X XI XII
What is the PTT used for
monitor intrinsic pathway
heparin therapy
What is the PT used for
monitor extrinsic pathway
coumadin therapy
What other tests may be used to monitor heparin therapy
Lee White clotting time
TT
What test is used for Factor XIII
5M urea solubility
The extrinsic system is initiated by
tissue factor III
The intrinsic system is initiated by
exposure to collagen
activation of contact factor XII
plt factor III
What will interfere with synthesis of Vit K dependent factors
Coumadin
What substance works with anti-thrombin III to neutralize thrombin
Heparin
Antidote for heparin
protamine sulfate
What is the principle of the fibrometer
completion of an electrical circuit between 2 electrodes by formation of a clot
What is the principle of the Coagulyzer, Coag-A-mate, MLA
detection of optical density changes in a cuvet by the photocell when clot is formed
Bleeding time test, what is it used for and is it performed
assess plt function and ability to form a clot
make a puncture wound in the superficial area and monitor the time needed to stop
Clot retraction, what it’s used for and what conditions does it indicate?
Fibrinogen and Hct must be normal
measures time for clot to lyse 0-2 hours
thrombocytopenia and Glanzmanns thrombasthenia
Which factors have an enzymatically active form
not V, VII, XIII
What is used in substitution testing
absorped plasma and aged serum
pinpoints factor deficiencies
How is sunstitution testing done
prior to testing with reagents, sample should be mixed with normal plasma and deficiency corrected. If not, a circulating anticoag should be suspected
Overall competence check of coag system would include
PT PTT bleeding time clot solubility test (XIII) fibrinogen
Haemans
XII
Christmas
IX
Stuart Power
X
Hemophilia A
VIII
Parahemophilia
V
Fibrinolysis depends on action of ? ?
plasmin
What is the coag test for fibrinolysis
euglobulin lysis est
First stage of coag
Plasma thromboplastin
Prolonged PTT indicated deficiency of ? ?
Fibrinogen
How ia anticoag adjusted if Hct is 55% or more
Increase volume
abnormal PT, normal PTT
VII
normal PT, abnormal PTT
IX
normal BT, abnormal clotting, normal PT, abnormal PTT
VIII