Mixing Studies
Factors
Coagulation
Tests
Von Willebrand disease
100
What are the vitamin K dependent clotting factors?
Factors II, VII, IX, and X
Proteins C and S
100
Amyloidosis has been associated with an acquired deficiency of which factor?
factor X
physiology of amyloidosis causing AFXD is due to the shortened half-life of factor X due to the binding of the factor to amyloid fibrils
100
Which protein is deficient in Thrombotic Thrombocytopenic Purpura?
ADAMSTS13
(a disintegrin and metalloproteinase with thrombospondin type 1 motif, member 13 )
100
In a factor VIII or IX inhibitor assay, the amount of inhibitor quantified by the assay is expressed as _______, where one ___ of inhibitor is that amount of inhibitor that destroys half of the factor VIII or IX:C activity in an equal mixture of patient and normal plasma.
Bethesda Unit (BU)
100
Where is vWF synthesized and stored?
endothelial cells (Weibel-Palade bodies) and megakaryocytes (platelet alpha granules)
200
What is the main purpose of thrombin time when included in mixing study?
detect presence of heparin
200
What is the half life of factor 7, 8, and 9?
4-6, 8-12, 16-24
200
Which blood product may be indicated based on this TEG finding?
cryoprecipitate - low CFF, low fibrinogen
200
Which test is frequently combined with a platelet neutralisation procedure to demonstrate the phospholipid specificity of the antibody as a screening test for lupus anticoagulant?
dilute Russell viper venom test (DRVVT)
As the RVV directly activates Factor X, the test is unaffected by deficiencies of Factors XII, XI, IX or VIII.
200
Which vWD is autosomal recessively inherited?
Type 2N; all other are transmitted autosomal dominant
300
a PTT mixing study that shows no immediate or incubated correction (thrombin time is also normal) most likely indicates:
lupus anticoagulant.
300
which factor, together with tissue factor, activates factor X?
factor VII
300
What is the formula for INR?
INR = [patient PT/Mean normal PT] raised to ISI
300
gold standard diagnostic test for detecting clinically relevant (platelet-activating) heparin-induced thrombocytopenia (HIT)
serotonin release assay
300
in type IIB, what is the defect and what would be notable on platelet aggregometry?
increased affinity of large vWF multimers for platelet binding to GPIb. Ristocetin induces aggregation at low dose (normally there is no aggregation with low dose ristocetin).
400
a PTT mixing study that shows immediate correction but prolongation after incubation is characteristic of what?
factor VIII inhibitor
400
Protein C inactivates which factors?
factors Va and VIIIa
400
Bernard Soulier or vWD
400
A patient has a positive clot solubility test in 5 molar urea solution. He is most likely to have a deficiency of which coagulation factor?
Factor XIII
400
Which of the type 2 vWD mimics hemophilia A and why?
type 2N - factor VIII are quite low (<10%) because there is a defect in the factor VIII binding region of vWF resulting in rapid turnover of unbound FVIII
500
Which factor deficiency is not associated with bleeding?
factor 12
500
What are factor III and factor IV?
factor III: tissue factor
factor IV: calcium
500
An infant born at term is noted to have bleeding from the umbilical cord stump. In childhood, he has poor wound healing. After puberty, is found to have infertility. As a teenager he develops an intracerebral hemorrhage. Laboratory studies include a prothrombin time 12 seconds, partial thromboplastin time 25 seconds, platelet count 244,000/microliter. What is the problem?
factor XIII deficiency
Factor XIII, which stabilizes fibrin clots, can be deficient, but this is extremely rare. Bleeding is first observed in the neonatal period. Patients may have poor wound healing, male infertility, abortion, and intracerebral hemorrhage.
500
most coagulation tests require collection of blood in what color tube?
blue top (usually light blue) (3.2% sodium citrate)
500
Which two types of vWD should NOT get desmopressin?
type 2B and platelet-type vWD because release of abnormal vWF may induce thrombocytopenia