Hemostasis Harr
factor VIII inhibitors occur in what percent of patients with factor VIII deficiency?
10-20%
which ratio of anticoagulant to blood is correct for coag procedures?
1:9
what is the approximate incidence of antiphospholipid antibodies in the general population?
2%
what test is used to monitor heparin therapy?
APTT
TTP differs from DIC in that:
APTT is normal in TTP but prolonged in DIC
PT: prolonged APTT: prolonged platelet: decreased which disorder?
DIC
fibrin monomers are increased in which of the following?
DIC
hemolytic uremic syndrome (HUS) is associated with:
E. Coli 0157
what test is commonly used to monitor warfarin therapy?
INR
a prolonged APTT is corrected with factor VIII-deficient plasma but not with factor IX-deficient plasma. which factor is deficient?
IX
which coag test would be abnormal in a vitamin K deficient patient?
PT and APTT
which test would be abnormal in a patient with factor X deficiency?
PT and APTT
a 50 year old man has been on heparin for the past 7 days. which combination of the tests is expected to be abnormal?
PT, PTT, TT
neurological findings may be commonly associated with which of the following disorders?
TTP
a prolonged APTT and PT are corrected when mixed with normal plasma. which factor is most likely deficient?
V
which of the following clotting factors are activated by thrombin that is generated by tissue pathway (TF-VIIa)?
V, VIII
what clotting factors are inhibited by protein S?
Va and VIIIa
which factor deficiency is associated with a prolonged PT and PTT?
X
which of the following clotting factors are measured by the APTT test?
XII, XI, IX, VIII, X, V, II, I
which of the following clotting factors plays a role in clot formation in vitro, but not in vivo?
XIIa
which protein is the primary inhibitor of the fibrinolytic system?
a2- antiplasmin
which of the following is a predisposing condition for the development of DIC?
adenocarcinoma
which of the following is associated with an abnormal platelet aggregation test?
afibrinogenemia
which defect characterizes grays syndrome?
alpha granule defect
which of the following is correct regarding acquired thrombotic thrombocytopenic purpura?
autoimmune disease
which of the following tests is most likely to be abnormal in patients taking aspirin?
bleeding time
which results would be expected for the PT and APTT in a patient with polycythemia?
both prolonged
the P2Y12 ADP receptor agonist assay may be used to monitor platelet aggregation inhibition to which of the following drugs?
clopidogrel (plavix)
which of the following platelet aggregating agents demonstrates a monophasic aggregation curve when used in optimal concentration?
collagen
hereditary hemorrhage telangiectasia is a disorder of:
connective tissue
aspirin prevents platelet aggregation by inhibiting the action of which enzyme?
cyclo-oxygenase
factor V Leiden promotes thrombosis by preventing:
deactivation of factor Va
which of the following may be associated with thrombotic events?
decreased protein C
which of the following is an appropriate screening test for the diagnosis of lupus anticoagulant?
diluted russells viper venom test (DRVVT)
a protein that plays a role in both coagulation and platelet aggregation is:
factor I
the most suitable products for treatment of factor VIII deficiency is:
factor VIII concentrate
when performing a factor VIII activity assay, a patients plasma is mixed with:
factor VIII deficient plasma
which clotting factor is not measured by PT and APTT tests?
factor WIII
the APTT is sensitive to a deficiency of which clotting factor?
factor X
normal PT and APTT results in a patient with a poor would healing may be associated with:
factor XIII deficiency
normal platelet adhesion depends upon:
glycoprotein Ib
which of the following is a characteristic of low molecular weight heparin?
has a longer half life than unfractionated heparin
one of the complications associated with a severe hemophilia A is:
hemarthrosis
the following results were obtained on a patient: normal platelet count and function normal PT prolonged APTT which of the following disorders is most consistent with these results?
hemophilia A
a prolonged thrombin time is indicative of which of the following antithrombotic therapies?
heparin
thrombocytopenia may be associated with:
hypersplenism
the following lab results were obtained from a 40 year old woman PT- 20 seconds APTT- 50 seconds thrombin time- 18 seconds what is the most probable diagnosis?
hypofibrinogenemia
which of the following is associated with post transfusion purpura (PTP)?
immune mediated thrombocytopenia/alloantibodies
which test result would be normal in a patient with dysfibrinogenemia?
immunologic fibrinogen level
thrombotic thromocytopenic purpura is characterized by:
increased platelet aggregation
factor XIII deficiency is associated with:
increased risk of thrombosis
which of the following complications may occur as a result of decreased tissue factor pathway inhibitor?
increased thrombotic risk
which statement about the fibrinogen/fibrin degradation product test is correct?
it detects late degradation products
which characteristic describes antithrombin (AT)?
it is a cofactor of heparin
which statement about coumadin (warfarin) is accurate?
it is not recommended for pregnant lactating women
which of the following characterizes vitamin K?
it is required for carboxylation of glutamate residues of some coag factors
which of the following is correct regarding the INR?
it standardizes PT results
which statement regarding protein C is correct?
its activity is enhanced by protein S
which of the following is a characteristic of classic hemophilia A?
mild to severe bleeding episodes
which of the following antibodies is used in the D-dimer assay?
monoclonal against D-dimer
several hours after birth, a baby boy develops petechiae and purpura and a hemorrhagic diathesis. the platelet count is 18x10^9. what is the most likely explanation for the low platelet count?
neonatal alloimmune thrombocytopenia
diagnosis of lupus anticoagulant is confirmed by which of the following criteria?
neutralization of the antibody by high concentration of platelets
when performing platelet aggregation studies, which set of platelet aggregation results would most likely be associated with bernard-soulier syndrome?
normal platelet aggregation to collagen, ADP, and epinephrine; decreased aggregation to ristocetin
which set of platelet responses would be most likely associated with glanzmanns thrombasthenia?
normal platelet aggregation to ristocetin; decreased aggregation to collagen, ADP, and epinephrine
an abnormal APTT caused by a pathological circulating anticoagulant is:
not corrected with normal plasma
a patient with a prolonged PT is given intravenous vitamin K. the PT corrects to normal after 24 hours. what clinical condition most likely caused these results?
obstructive jaundice
what substrate is used in a chromogenic factor assay?
p-nitroanaline
the lupus anticoagulant affects which of the following tests?
phospholipid dependent assays
which of the following lab tests is helpful in the diagnosis of aspirin resistance?
platelet aggregation
lumi-aggregation measures:
platelet aggregation and ATP release
which of the following instruments can be used to evaluate platelet function?
platelet aggregometer, verifynow, PFA 100
which of the following test results is normal in a patient with classic von Willebrands disease?
platelet count
storage pool deficiencies are defects of:
platelet granules
which of the following drugs inhibits ADP mediated platelet aggregation?
prasugrel
which results are associated with hemophilia A?
prolonged APTT, normal PT
which of the following abnormalities is consistent with the presence of lupus anticoagulant?
prolonged APTT/thrombosis
which of the following prevents platelet aggregation?
prostacyclin
thrombin-thrombomodulin complex is necessary for activation of:
protein C
a standard 4.5 mL blue top tube filled with 3 mL of blood was submitted to the lab for PT and APTT tests. the sample is from a patient undergoing surgery the following morning for a tonsillectomy. which of the following is the necessary course of action by the tech?
reject the sample and request a new one
which of the following is associated with multiple factor deficiencies?
severe liver disease
prothrombin G20210A is characterized by which of the following causes and conditions?
single mutation of prothrombin molecule/thrombosis
the anticoagulant of choice for most routine coag studies is:
sodium citrate
in primary fibrinolysis, the fibrinolytic activity results in response to:
spontaneous activation of fibrinolysis
which of the following is a characteristic of acute immune thrombocytopenic purpura?
spontaneous remission within a few weeks
which statement is correct regarding sample storage for the prothrombin time?
stable for 24 hours is the sample is capped
which of the following statements is correct regarding the D-dimer test?
test has a negative predictive value
a modification of which procedure can be used to measure fibrinogen?
thrombin time
which lab test is affected by heparin therapy?
thrombin time
bernard-soulier syndrome is associated with:
thrombocytopenia and giant platelets
what reagents are used in the PT test?
thromboplastin and calcium
aspirin resistance may be associated with:
thrombosis
fletcher factor (prekallikrein) deficiency may be associated with:
thrombosis
plasminogen deficiency is associated with:
thrombosis
which of the following is associated with antithrombin deficiency?
thrombosis
which of the following is most commonly associated with activated protein C resistance?
thrombosis
which of the following initiates in vivo coagulation by activation of factor VII?
tissue factor
which of the following is referred to as an endogenous activator of plasminogen?
tissue plasminogen activator
the most common subtype of classic von willerbrands disease is:
type 1
which drug promotes fibrinolysis?
urokinase
PT-normal APTT- prolonged bleeding time- increased platelet count- normal aggregation to ristocerin- abnormal what disorder may be indicated?
von willebrands disease
