Coagulation Lab CEs

Factor V is primarily involved in the a. Extrinsic b. Intrinsic c. Fibrinolytic d. common e. none of the above

D. common

Which of the following tests is used to monitor therapy with unfractionated heparin? a. PT b. APTT c. Fibrinogen assay d. Platelet function assay

b. APTT

A patient with a history of frequent mild bleeding episodes has the following results: Normal PT Prolonged APTT corrected by normal plasma during mixing studies. What could be the cause of the initial APTT prolongation? a. Factor VII deficiency b. Factor IX deficiency c. Factor V deficiency d. A circulating inhibitor is present

b. Factor IX deficiency APTT is corrected so it can't be an inhibitor

Hemophilia A is associated with a deficiency in which coagulation factor a. Factor IX b. Factor VIII c. Factor X d. Factor V

b. Factor VIII

A severe hemophiliac with a Factor VIII activity of less than 1% is actively bleeding due to a serious accident. The blood product of choice is a. Single-donor plasma b. Factor VIII concentrate c. Factor IX concentrate d. Cryoprecipitate

b. Factor VIII concentrate

Which of the following factor deficiencies is associated with either no bleeding or only minor bleeding tendency, even after trauma or surgery?

b. Factor XII

The dissolution of a clot with 5M urea indicates which one of the following factors deficiencies? a. Factor II b. Factor XIII c. vW disease d. Lupus anticoagulant e. Factor IX

b. Factor XIII Responsible for formation of stable fibrin clot

The laboratory completed a mixing a study. The results are as follows: Initial APTT: 167 sec 1:1 mix APTT: 158 sec Which of the choices below most likely explain the results for the patient? a. Factor VIII deficiency b. Immediate acting coag inhibitor c. Time/temp dependent coag inhibitor d. Factor VII deficiency

b. Immediate acting coag inhibitor

Acute ITP is most often associated with which of these populations? a. Newborns b. Kids ages 1-7 c. Adults 20-40 d. seniors over the age of 65

b. Kids ages 1-7

Which of the following tests could be used to determine whether an abnormal screening coagulation test is caused by a factor deficiency or an inhibitor? a. Bleeding time b. Mixing studies c. Fibrin split products d. Fibrinogen assay

b. Mixing studies If screening test is corrected, factor deficiency If screening test isn't corrected, inhibitor

Warfarin-based oral anti-coagulant therapy is commonly monitored with a. APTT b. PT/INR c. APTT and PT d. Thrombin Time

b. PT/INR Warfarin inhibits Vitamin K dependent factors

Which of the following coagulation factors is considered to be labile?

b. V

Which of the following factors show an increase in liver disease?

b. VIII

Which of the following laboratory findings is associated with factor XIII deficiency?

b. clot solubility in 5M urea solution

Which of the following test results are NOT characteristic of DIC? a. decreased fibrinogen concentration b. negative test for fibrin split products (D-dimer) c. decreased platelet count d. prolonged PT

b. negative test for fibrin split products (D-dimer)

The best test to determine if a sample is contaminated with heparin is: A. fibrinogen B. thrombin time C. prothrombin time D. stypven time

b. thrombin time

This assay would be used to help rule out heparin contamination in coagulation sample: a. Protein C assay b. Thrombin time c. PT d. APTT

b. thrombin time

A defect in which of the following factors causes impaired platelet adhesion and aggregation? a. Stuart-Prower factor (X) b. vWF (VIII) c. Hageman factor (IX)

b. vWF (VIII)

What is the correct blood to anticoagulant ratio for coagulation tests? a. 4:1 b. 5:1 c. 9:1 d. 10:1

c. 9:1

Which of the following is not a likely cause of an abnormal thrombin time? a. Fibrin split products b. Heparin c. Aspirin d. Dysfibrinogenemia

c. Aspirin Affects primary platelet function

APC resistance is confirmed by the molecular test for

c. FVL

The absence of which clotting factor causes NO bleeding tendency? a. Anti-hemophiliac b. Stuart Prower c. Hageman d. Labile

c. Hageman

Plasma exchange is the current treatment for which of these conditions? a. Acute ITP b. Chronic ITP c. TTP

c. TTP

To distinguish between hemophilia and vWD, a patient with vWD would have what tests results

c. abnormal APTT, platelet screen, and ristocetin cofactor

What are the primary reagents used in the APTT? a. Thromboplastin and sodium chloride b. activated partial thromboplastin and potassium c. activated partial thromboplastin and calcium d. actin and sodium chloride

c. activated partial thromboplastin and calcium ????

The presence of RBCs with altered morphology (schistocytes) has a close association with all of the following conditions except a. DIC b. severe burns c. bone marrow metastasis d. TTP

c. bone marrow metastasis

Excess D-dimer indicate that clots have been: A. converted to fibrin monomers B. released into circulation C. formed and are being excessively lysed D. stimulated to activate plts

c. formed and are being excessively lysed

Which of the following statements regarding Vit K is not true?

c. heparin inhibits the action of Vit K

A deficiency of protein C is associated with which of the following

c. increased risk of thrombosis

Which of the following is a common clinical symptom that is directly related to thrombocytopenia? a. Shortness of breath b. joint paint c. petechiae d. fever

c. petechiae

In the APTT test, the patients plasma is mixed with

c. phospholipid (innovin) and calcium

Which of the following lab results would you see in patients with DIC?

c. prolonged PT, decreased fibrinogen, decreased platelet count, increased FDP

Which of the following mechanism involve a series of interrelated chemical processes that lead to the formation of durable fibrin strands? a. fibrinolysis b. Primary hemostasis c. secondary hemostasis d. vasoconstriction

c. secondary hemostasis

Biological assays from AT III are based on the inhibition of

c. serine proteases

The activation of plasminogen to plasmin resulting in the degradation of fibrin occurs by

c. tPA

A mixing study should be performed within how many hours of collection?

4 hours

The international normalized ratio is a calculation that is used to

standardize PT results between different reagent sensitivities

What organ is associated with the production of the majority of the clotting factors?

the liver

Hemophilia B is the result of a hereditary deficiency in which coagulation factor?

Factor IX

Which of these factors may be deficient if both the PT and APTT are prolonged? a. Factor II b. Factor VII c. Factor VIII d. Factor XI

a. Factor II part of common pathway

Which of the following factors require Vitamin K for their synthesis in the liver? a. Factor II b. Factor VII c. Factor IX d. Factor XI e. Factor XII

a. Factor II b. Factor VII c. Factor IX Vitamin K dependent factors are 7, 9, 10, 2 Causes increased PT if deficient

Which of the following is considered the most common coagulation inhibitor? a. Lupus anticoagulant b. Anti-factor II c. Anti-factor V d. Anti-factor X

a. Lupus anticoagulant

A patient taking 10 mg per day of coumadin would have what test result be impacted the most?

a. Protein C levels

Plasma from a patient with lupus coagulation inhibitor can show:

a. a prolonged APTT and normal PT

Prothrombin is

a. a protein formed by the liver in the presence of vitamin K

LMWH is monitored by

a. anti-Xa assay

What is the mechanism of heparin-induced thrombocytopenia? a. antibodies directed against platelet factor 4 and heparin complex b. administration of toxic doses of heparin that destroy platelets c. abrupt cessation of heparin therapy

a. antibodies directed against platelet factor 4 and heparin complex

Acute DIC is characterized by:

a. hypofibrinogenemia

In essential thrombocythemia, the platelets are usually a. increased in number and functionally abnormal b. normal in number and functionally abnormal c. decreased in number and functional d. decreased in number and functionally abnormal

a. increased in number and functionally abnormal

The most potent plasminogen activator in the contact phase of coagulation is

a. kallikrein

What minimum level of a particular factor will cause the APTT test to become prolonged? a. less than 40% b. less than 50% c. less than 60% d. less than 70%

a. less than 40%

All of the following statements describe a method by which platelets aid coagulation EXCEPT: a. lower BP by releasing heparin b. catalyze coagulation by releasing platelet factor 3 c. cause blood vessels to constrict by releasing serotonin d. form a platelet plug to stop blood flow

a. lower BP by releasing heparin

Which of the following is a characteristic of Factor XII deficiency?

a. negative bleeding history

When performing a mixing study, you aliquot your sample plasma and the pooled normal plasma to create your "mix". you then place the sample in a water bath for 90 minutes before running your new mixed sample. What is wrong with that procedure? a. you don't need to incubate your sample b. you have forgotten to add reagent c. you have not run a PT or APTT on the new mix before incubating d. you have incubated too long

c. you have not run a PT or APTT on the new mix before incubating

Which of the following is a genetic platelet disorder characterized by giant platelets, abnormal screening tests for platelet function, and moderate to severe thrombocytopenia? a. Glanzmann Disorder b. Hemophilia A c. DIC d. Bernard-Soulier syndrome

d. Bernard-Soulier syndrome

The prothrombin time test requires that the patients citrated plasma be combined with

d. Ca 2+ and thromboplastin

A specimen drawn from an indwelling catheter that was contaminated with heparin would be indicated by: a. normal PT and APTT b. abnormal PT and APTT c. Prolonged APTT and prolonged reptilase time test d. Prolonged APTT and normal reptilase time test

d. Prolonged APTT and normal reptilase time test Reptilase not inhibited by heparin

Primary hemostatic processes resulting from vascular damage include all of the following EXCEPT: a. Collagen activates glycoprotein IIb/IIIa during platelet activation b. vWF mediates platelet adhesion c. Platelet granule release and fibrinogen mediate platelet aggregation d. Rapid and intermediate vascular dilation occurs e. Both B and C

d. Rapid and intermediate vascular dilation occurs Vasoconstriction occurs, not dilation

The two factors that differentiate liver disease from Vit K deficiency are

d. V and VII

Which of the following factors does not affect the result of the APTT? a. X b. IX c. VIII d. VII

d. VII APTT measures Extrinsic pathway

Which of the following laboratory results is characteristic for a patient with vW disease? a. Decreased bleeding time b. normal factor VIII level c. normal platelet function tests d. abnormal platelet aggregation response to ristocetin e. A and C

d. abnormal platelet aggregation response to ristocetin

Which of the following tests may be used to confirm screening test results for a lupus anticoagulant (or anti-phospholipid antibody)? a. APTT b. PT c. factor assays d. dRVVT

d. dRVVT

Which of the following is Vit K dependent?

d. factor VII

Which of the following factors is NOT involved in the initial contact phase of the intrinsic pathway? a. factor XII b. Fitzgerald factor (HMWK) c. Fletcher factor (PK) d. Factor X

d. factor X

Heparin acts by: A. precipitating fibrinogen B. binding Ca C. activating plasmin D. inhibiting thrombin

d. inhibiting thrombin

What would be a probable diagnosis for a habitual alcoholic with slight elevations in the PT and APTT tests? a. lupus inhibitor b. DIC c. platelet antibody d. liver disease

d. liver disease

The APTT

d. monitors heparin therapy

A prolonged thrombin time and a normal dRVVT are characteristic of

d. therapeutic heparinization

DIC is associated with all of the following except a. Septicemia b. Obstetric emergency c. intravascular hemolysis d. thrombocytosis

d. thrombocytosis

Hageman factor (factor XII) is involved in each of the following reactions except

d. transformation of fibrinogen to fibrin

What may prevent the detection of lupus anticoagulant in a plasma sample of the blood used for testing is not centrifuged for a sufficient time?

increased platelet in plasma sample