An initial prenatal evaluation at 10 weeks is conducted on a healthy female.
PT, aPTT and
fibrinogen are normal with the exception of her platelet count, which is 42,000/ml. The PBS
shows platelet clumps. What is the next step?
A. conduct a workup for autoimmune disease
B. evaluate for risk of thromboembolism
C. recollect the sample in EDTA
D. recollect the sample in sodium citrate
The initial platelet adhesion to subendothelial matrix proteins is abnormal in:
A. vWD and Bernard-Soulier syndrome
B. hemophilia A or B
C. GPllb/llla inhibitors
D. Factor XIII deficiency
A 2-year-old child presents with recurrent epistaxis, gum bleeding and occasional hematuria,
upon physical exam showed petechiae and ecchymoses. The patient is not on any medication.
PT and aPTT and platelet count are normal. Platelet function screen tests are abnormal, and a
platelet aggregation test is ordered. Results are: Absent aggregation with ADP, collagen,
epinephrine. RIPA: within reference range
The differential diagnosis should include:
A. Berard-Soulier
B. Glanzmann thrombasthenia
C. vWD
D. grey platelet syndrome
Disorders of platelet aggregation are found in:
A. vWD
B. Bernard-Soulier
C. Glanzmann thrombasthenia
D. storage pool deficiency
A 65-year-old male has a valve replacement, and 5 days postoperatively his platelet count had
fallen to 80,000 after an initial count of 320,000. Also noted is the swelling of his right calf. The
following day the platelet count is 30,000. What should be investigated, and what therapeutic
step is appropriate?
A. platelet disorder; administer platelets
B. postoperative bleeding; administer plasma
C. HIT; administer direct thrombin inhibitor
D. HIT; administer LMWH
A 70-year-old female with metastatic ovarian carcinoma shows elevated PT and aPTT, platelets
15,000/mm3 and an elevated D-dimer. The differential diagnosis should include:
A. TTP
B. APS
C. DIC
D. HUS
A patient with a platelet count of 223 x 109/L and an abnormal PFA most possibly has:
A. decreased platelet production
B. defective platelet function
C. increased platelet production
D. increased platelet destruction
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 TT 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
A new PT reagent is being set up in the coagulation laboratory. The ISI of the new reagent is 1.0;
the previous reagent had an ISI of 2.1. The new reagent is said to be:
A. more sensitive
B. less sensitive
C. insensitive
D. n סchange
A 42-year-old male presents with fatigue, difficulty breathing, and tingling in the hands and
feet. The laboratory results shown in this table are obtained:
PT 25.6 seconds (11.5-13.9 seconds)
aPTT 77.5 seconds (25.0-35. 7 seconds)
Hb 23.5 g/dl
Hct 76.2%
The clinician questioned the results, as the patient had no bleeding symptoms. This result could
be caused by:
A. aplastic anemia
B. polycythemia vera
C. chronic lymphocytic leukemia
D. sickle cell disorder
An 11-year-old female presents to the ED with hemarthrosis in her knee after an injury. This is
the third incidence of hemarthrosis. Patient presents with a pronged PT of 27 seconds and a
normal aPTT of 30 seconds, with a normal platelet count. The PT corrects to 13 seconds upon a
mixing study. Possible diagnosis may be a deficiency of:
A. factor XI
B. factor VII
C. factסr VIII
D. factor IX
A 68-year-old male presents with tingling in hands and feet, an irregular heartbeat, severe
fatigue and difficulty in swallowing. Coagulation results show an abnormal PT and aPTT, which
completely correct to normal with a mixing study. The factor that most likely contributes to this
is a deficiency in:
A. factor VII
B. factor X
C. factor VIII
D. factor XIII
A mixing study will remain uncorrected in a patient with:
A. hemophilia A
B. heparin
C. HIT
D. hemophilia B
The type of vWD that has enhanced ristoceti חactivity is:
A. type 2A
B. type 2B
C. type 2M
D. type 2N
When comparing acute DIC vs chronic DIC, acute DIC presents with:
A. normal PT
B. normal aPTT
C. decreased d-dimer
D. decreased platelets
What coagulation plasma protein should be assayed when platelets fail to aggregate properly?
A. Factor VIII
B. Fibrinogen
C. Thrombin
D. Factor X
What serine protease forms a complex with factor VIIIa, and what is the substrate of this
complex?
A. Factor VIIa, factor X
B. Factor Va, prothrombin
C. Factor Xa, prothrombin
D. Factor IXa, factor X
What two regulatory proteins form a complex that digests activated factors V and VIII?
A. TFPI and Xa
B. Antithrombin and protein C
C. APC and protein S
D. Thrombomodulin and plasmin
What are the primary roles of VWF?
A. Inhibit excess coagulation and activate protein C
B. Activate plasmin and promote lysis of fibrinogen
C. Mediate platelet adhesion and serve as a carrier molecule for factor VIII
D. Mediate platelet aggregation via the GP IIb/IIIa receptor
What factor becomes deficient early in liver disease, and what assay does its deficiency
prolong?
A. Prothrombin deficiency, the PT
B. Factor VII deficiency, the PT
C. FVIII deficiency, the PTT
D. Factor IX deficiency, the PTT
Which of the following conditions causes a prolonged thrombin time?
A. Antithrombin deficiency
B. Prothrombin deficiency
C. Hypofibrinogenemia
D. Warfarin therapy
What therapy may be used for a hemophilic boy who is bleeding and who has a high FVIII
inhibitor titer?
A. rFVIIa
B. Plasma
C. Cryoprecipitate
D. FVIII concentrate
Which of the following assays is used to distinguish vitamin K deficiency from liver disease?
A. PT
B. Protein C assay
C. Factor V assay
D. Factor VII assay
Patient X presents with pronounced epistaxis, hematoma and disabled joints, the patients has
history of severe bleeding episodes in the past. Molecular studies confirm mutation in the gene
encoding the GPIbα of the vWFR. Which of the following laboratory test findings correlates with
this patient’s condition?
A. Abnormal platelet response to arachidonic acid
B. Abnormal platelet response to ristocetin
C. Abnormal platelet response to collagen
D. Thrombocytosis
Scenario: What may happen if you use the lavender top tube to run the PT/PTT tests while all
QC levels passed?
