BOC Laboratory Determinations

A new PT reagent is being set up in the coagulation laboratory. The ISI of the new reagent is 1.0 vs the previous reagent with an ISI of 2.1. The new reagent is said to be: A. more sensitive B. less sensitive C. insensitive D. no change

A

A patient is taking 10 mg per day of Coumadin (warfarin). The results of which of the following laboratory tests will be most impacted? A. protein C B. antithrombin C. factor V Leiden D. factor VIII

A

A patient presents with aPTT of 49 seconds (25 - 35 seconds). A mixing study is performed with results as follows: 1:1 mix = 39.8 seconds pooled normal plasma = 32.0 seconds The results indicate: A. circulating anticoagulant B. factor deficiency C. decreased platelets D. fibrinolysis

A

A patient presents with aPTT of 62.5 seconds (25 - 35 seconds) and the only factor that is decreased is factor XII. What is the clinical picture for this patient? A. negative bleeding history B. prolonged PFA C. decreased risk of thrombosis D. epistaxis

A

An orthopedic patient is placed on low molecular weight heparin after back surgery, in order to determine if the level of LMWH is therapeutic the test to monitored levels would be: A. anti-Xa assay B. aPPT C. PT D. anti-IIa assay

A

D-dimers are produced from: A. crosslinked and stabilized fibrin clots B. decreased fibrinogen and platelets C. plasminogen being converted to plasmin D. generation of thrombin from endothelial cells

A

The DRVV screen test will be prolonged in a patient with lupus due to the reagent containing? A. decreased concentration of phospholipid B. increased concentration of phospholipid C. hexagonal phase phospholipids D. bilayer phospholipids

A

A patient has been taking aspirin regularly for arthritic pain. Which one of the following tests is most likely to be abnormal in this patient? A. platelet count B. PFA 100 C. prothrombin time D. activated partial thromboplastin time

B

A patient has the following results: PT 12.1 seconds aPTT 52 seconds immediate 1:1 mixing study / patient = 50 seconds, pooled normal plasma = 32.7 seconds The next test that should be performed is: A. TCT B. DRVVT C. FVII D. PFA 100

B

A patient presents with a low protein S activity and low total and free protein S antigens. The C4b binding protein is normal. This is classified as: A. no deficiency B. type I C. type II D. type III

B

A sample is sent to the laboratory for an anti-Xa assay. The result of the PTT is 65.7 seconds. The result of the anit-Xa assay is 0.9 U/mL of heparin. The patient is on Lovenox. Their anti-Xa level is: A. subtherapeutic B. therapeutic C. supratherapeutic D. prophylactic

B

Activated protein C (APC) resistance is associated with a mutation in: A. thrombin B. factor V C. factor VIII D. protein C

B

In the Clauss fibrinogen assay the time for clot formation in plasma is measured after the addition of: A. calcium B. thrombin C. phospholipids D. fibrin

B

In the Clauss fibrinogen method, the time to clot formation in plasma is measured after the addition of: A. calcium B. thrombin C. phospholipids D. kaolin

B

The best test to determine if a sample contains residual heparin: A. fibrinogen B. thrombin time C. prothrombin time D. D-dimer

B

The following tracing is from a cardiac surgery patient using thromboelastography. This tracing shows the patient during cardiac surgery is: A. under-anticoagulated B. sufficiently anticoagulated C. over anticoagulated D. normal

B

The measurement principle that used factor Xa which is to a patient plasma and added to a substrate is a: A. factor assay B. chromogenic assay C. ELISA assay D. immunologic assay

B

The principle of platelet aggregation is based on: A. decreased light transmission B. increased light transmission C. decreased light absorbance D. increased light absorbance

B

What does the secondary wave of platelet aggregation seen with the biphasic low dose ADP and epinephrine response represent? A. increased binding to collagen B. release of platelet granules C. increased activation by collagen D. formation of fibrin dimers

B

Which of the following causes of thrombophilia most often presents as thrombic episodes with resistance to heparin? A. protein C deficiency B. antithrombin deficiency C. prothrombin G20210A deficiency D. factor V Leiden

B

Which of the following tests provides an appropriate laboratory confirmation of immune mediated heparin induced thrombocytpoenia (type 2)? A. anti-PF3 antibody B. serotonin release assay C. ristocetin induced platelet aggregation assay D. reptilase assay

B

A 42 year old male presented with fatigue, difficulty breathing, tingling in the hands and feet. The following laboratory results are obtained: PT. 25.6 (11.5 - 13.9) aPTT 77.5 (25.0 - 35.7) Hgb 23.5 g/dL Hct 76.2% The clinician questioned the results, as the patient had no bleeding symptoms. This result could be cause by: A. aplastic anemia B. polycythemia vera C. chronic lymphocytic leukemia D. sickle cell disorder

B (high HGB)

A deficiency of protein C is associated with which of the following? A. prolonged aPTT B. decreased fibrinogen level (<100 mg/dL) C. increased risk of thrombosis D. spontaneous hemorrhage

C

A patient presents with an aPTT of 24 seconds (25 - 35 seconds) which is below the normal range. A possible explanation for this result is the presence of a(n): A. DVT B. lupus anticoagulant C. acute phase reactant D. inhibitor

C

A patient sample has been tested in the routine laboratory with a PT and an aPTT. Six hours later factor assays are ordered on the same sample. Which factor is the most labile? A. II B. VII C. VIII D. X

C

An aPTT result from the main laboratory is 67 seconds, and is frozen to be saved for additional lupus testing in the special coagulation laboratory. The aPTT repeated the next day is 37 seconds. This can be caused by: A. wrong sample saved B. factors were activated C. platelets contaminated sample D. different reagent sensitivity used

C

Biological assays for antithrombin (AT) are based on the inhibition of: A. factor VIII B. heparin C. serine proteases D. anti-AT globulin

C

The following platelet aggregation tracing represents: A. von Willebrand disease B. storage pool disease C. Glanzmann thrombasthenia D. aspirin

C

What are parents with homozygous protein C deficiency particularly at an increased risk of developing? A. posttransfusion purpura B. warfarin skin necrosis C. purpura fulminans D. thrombocytophilia

C

What is the most common cause of inherited thrombophilia? A. antiphospholipid syndrome B. prothrombin G20210A mutation C. factor V Leiden D. hyperhomocysteinemia

C

Which of the following platelet responses is most likely associated with type IIb von Willebrand disease? A. decreased platelet aggregation to low dose ristocetin B. normal platelet aggregation to low dose ristocetin C. increased aggregation to low dose ristocetin D. decreased aggregation to high dose ristocetin

C

APC resistance is confirmed by the molecular test for: A. PAI 1 4G/5G B. MTHFR C. FVL D. G20210A

C (Factor V Leiden)

A patient has their coagulation blood sample drawn from a line. This is the only option for obtaining the sample. The PT is normal at 11.5 seconds, the aPTT is prolonged at 67 seconds, and the thrombin time is prolonged at 30 seconds. Based on this information how should testing proceed? A. factor assays testing should be performed B. a mixing study should be done C. a heparin neutralization should be done D. an inhibitor assay should be performed

C (drawn from line)

A patient is placed on clopidogrel. The clinician wants to determine if the dose is sufficient to impair platelet function. A platelet aggregation test is ordered. The agonist which would result in a decreased aggregation pattern would be: A. collagen B. epinephrine C. ristocetin D. adenosine disphosphate

D

A patient presents to the coumadin clinic with an INR of 3.1. He has mechanical heart valve. The level of anitcoagulant should be: A. decreased B. increased C. stopeed D. not adjusted

D

A platelet aggregation tracing appears to confirm the diagnosis of Glanzmann thrombasthenia in a patient presenting with a platelet disorder. How would these tracings look if they were performed using light transmittance optical density aggregation? A. decreased platelet aggregation to ristocetin B. increased platelet aggregation to ristocetin C. normal response for all agonists D. markedly decreased aggregation to epinephrine, ADP and collagen

D

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

D

Platelet aggregation will occur with the end production of: A. cyclooxygenase B. arachidonic acid C. prostacyclin D. thromboxane A2

D

The aPTT is a coagulation screening test that is also used to: A. evaluate the extrinsic coagulation pathway B. monitor Coumadin therapy C. require tissue thromboplastin D. monitor unfractionated heparin therapy

D

The following platelet aggregation responses were most likely associated with: A. storage pool disorder B. Glanzmann thrombasthenia C. aspirin ingestion D. hemophilia A

D

The following tracing represents a patient with: A. type 1 vW disease B. type 2 vW disease C. type 3 vW disease D. no vW disease

D

The test used to quantitate a factor inhibitor is the: A. factor assay B. multimer test C. ristocetin cofactor D. Bethesda assay

D

When a patient presents with an elevated factor VIII level, what test will be impacted? A. prolonged PT B. shortened PT C. prolonged PTT D. shortened PTT

D

Which of the following can affect the PFA 100 closure time? A. aspirin B. thrombocytopenia C. anemia D. all of the above

D

Which of the following proteins provides the binding site for heparin? A. protein C B. protein S C. factor X D. antithrombin

D

Whole blood evaluation of blood clotting can be performed by using thromboelastography. This methodology looks at: A. clot onset B. clot strength C. fibrinolysis D. all of the above

D

The results on a patient are as follows: PT 18.5 (11.0 - 13.5) aPTT 47.5. (24 - 35) thrombin time 14.0 (12 - 19) ATIII 82% (70 - 130%) protein C. 54% (77 - 167) protein S 48% (65 - 140%) activated protein C resistance 2.6 (>2.1) These results reflect: A. thrombophilia B. factor IX deficiency C. heparin D. warfarin

D (reduced protein C/S)