heme test ch 38 - 41, and 45
Which type of VWD gives a positive response to low-dose ristocetin-induced platelet aggregation?
2B
What is the normal bone marrow cellularity in the population older than 65 years?
30%
Why is the white count in a normal full-term newborn elevated shortly after birth?
An absolute increase in neutrophils occurs.
A patient arrives at the emergency department complaining of pain in the calf of his left leg and shortness of breath. A "stat" D dimer is ordered. Why is this useful information for this patient's care?
An elevated D dimer supports the possibility of deep vein thrombosis.
Which of the following is a disorder with absent platelet glycoprotein Ib/IX/V and in which the patient has moderate thrombocytopenia, large platelets, and normal aggregometry with all agents except ristocetin?
Bernard-Soulier syndrome
What procedure is used to quantitate a factor VIII inhibitor?
Bethesda assay
A patient in the intensive care unit has anemia, schistocytes, and thrombocytopenia. The PT and PTT are elevated, and the fibrinogen is low. What test to confirm what diagnosis would be appropriate?
D dimer to confirm acute DIC
What test is useful for detection of a female carrier of hemophilia A?
Factor VIII to VWF ratio
Which unusual laboratory finding may be present in sepsis-induced DIC?
Fibrinogen may be high because it is an acute phase reactant.
Which of the following is the most likely diagnosis for a patient with a normal platelet count and no aggregation with any agent except ristocetin?
Glanzmann thrombasthenia
A Complete blood count (CBC) is requested on a full-term newborn girl, and the following results are obtained: RBCs 5.07 × 1012/L Hemoglobin 14.4 Hematocrit 44.5% MCV 88fL White blood cells (WBCs 26.8 × 109/L Platelets 295 × 109/L What conclusion can be made regarding these data for this infant?
Hemoglobin, hematocrit, and MCV are all decreased.
A 67-year-old woman arrives at the emergency department with acute bleeding into the back of the throat. A coagulation screen is ordered with the following results: Prothrombin time (PT)12 seconds11-15 seconds Partial thromboplastin time (PTT)57 seconds25-37 seconds36 seconds (immediate) Fibrinogen450 mg/dL150-400 mg/dL What would be a reasonable next step to perform?
Incubate the 1:1 mix at 37° C for 1 hour and then repeat the PTT.
All of the following are normal peripheral blood RBC findings at birth in a full-term infant except
Mean cell volume (MCV) less than 90 fL
What coagulation screening test is the most sensitive for detecting mild liver disease?
PT
What tests are best to distinguish thrombotic thrombocytopenic purpura from DIC when a patient has schistocytes?
PT and PTT
Which of the following tests is increased in a patient with severe hemophilia A?
PTT
What tests should be performed on a regular basis on patients receiving therapeutic heparin?
PTT and platelet count
What is the most likely reason that the red blood cell (RBC) count remains elevated in a newborn for the first 2 weeks of life?
Partial anoxia exists in utero, and erythropoietin increases.
What is the mechanism for the platelet dysfunction in multiple myeloma and Waldenström macroglobulinemia?
Platelets are coated with paraprotein.
A thrombosis risk testing profile is ordered on a patient being treated with warfarin for a blood clot in the leg. Select the best course of action.
Recommend the testing be postponed until the warfarin is discontinued.
Why is there a relative lymphocytosis in a 2-year-old?
The absolute number of lymphocytes is increased as the immune system develops.
When the chromogenic assay for antithrombin is performed, which of the following is true?
The colored end-product intensity is inversely proportional to the antithrombin concentration.
What is important about the test systems used for detection of the lupus anticoagulant?
The patient plasma and normal plasma used for mixing studies should be platelet poor.
What is the best method to prevent warfarin-induced skin necrosis during treatment for thrombosis?
Use heparin for first 5 days in conjunction with warfarin.
A 21-year-old woman has a primary complaint of menorrhagia. Her coagulation screen gives the following results. rangeProthrombin time (PT)12.0 seconds11-15 seconds Partial thromboplastin time (PTT)40 seconds25-37 seconds Factor VIII activity35%50%-150% Platelet count225 × 109/L150-400 × 109/L What disorder is most likely?
VWD, type 1
Desmopressin acetate (DDAVP) is used to treat
VWD, type 1
What is the most serious clinical consequence of heparin-induced thrombocytopenia?
What is the most serious clinical consequence of heparin-induced thrombocytopenia?
Which of the following is true regarding testing for the diagnosis of vascular disorders?
Which of the following is true regarding testing for the diagnosis of vascular disorders?
An 85-year-old woman has a hemoglobin of 10.5 g/dL. This is
a sign of an underlying disease and requires further evaluation.
What substance is used to activate protein C in the chromogenic assay to determine its concentration?
a specific snake venom
Chemotherapy results in which of the following?
acquired hypoplastic thrombocytopenia
Which of the following makes a patient more prone to hemorrhage?
acute disseminated intravascular coagulation (DIC)
All of the following are often associated with thrombocytosis except
alcoholic liver disease
What are the primary clinical manifestations of essential thrombocythemia?
all of the above
What types of hemostatic complications are found in patients with myeloproliferative disorders?
all of the above
Which of the following is used to treat DIC?
all of the above
Which of the following screening tests would be normal when the plasma for the patient in Question 26 is analyzed?
all of the above
All of the following are common conditions or situations that interfere with platelet function except
allergic purpura
At what age is it normal for bone marrow cellularity to be 80% to 90% (i.e., has very little fat)?
at birth
Iron deficiency anemia in older adults is most often a result of
bleeding in the gastrointestinal tract.
Which of the following patient groups is most commonly diagnosed with acute immune thrombocytopenic purpura?
children after having an infection
What is the best test to perform if a patient's PTT does not rise after the typical heparin dose?
chromogenic antithrombin
A 28-year-old woman sees her family physician complaining of easy bruising and menorrhagia. She has a platelet count of 60 × 109/L. All other hematology and routine coagulation tests are normal. She has a platelet-associated immunoglobulin G (IgG) autoantibody in her serum. Which of the following is most likely?
chronic immune thrombocytopenic purpura
Which of the following is most commonly seen in the population older than70 years?
chronic lymphocytic leukemia
Which of the following results puts the patient at an increased risk for thrombosis?
chronically elevated fibrinogen
Which of the following is the cause for most strokes and heart attacks in the United States?
consequences of thrombotic events
What is the most common infectious cause of congenital neonatal megakaryocytic hypoplasia?
cytomegalovirus
What is the probable cause for thrombotic thrombocytopenic purpura?
deficiency of a metalloprotease needed to enzymatically degrade unusually large von Willebrand factor (VWF) multimers
Platelet count and function studies are performed on a patient with a history of easy bruising, and the following results are obtained: Platelet count295 × 109/L Platelet function assayProlonged Platelet aggregation with epinephrinePrimary but no secondary wave Platelet aggregation with low-dose adenosinediphosphate (ADP)Primary but no secondary wave Platelet aggregation with ristocetinNormal What is the most likely diagnosis for this patient?
dense granule deficiency
Which of the following is the most common cause of acquired platelet dysfunction?
drugs, especially aspirin
Which of the following is an expected finding in DIC?
elevated D-dimer and fibrin split products
Why does prothrombin G20210A increase the risk of thrombosis?
elevates prothrombin levels
Which of the following proteins is the best test to distinguish moderate to severe liver disease from vitamin K deficiency?
factor V concentration
In what is a patient with the following coagulation test results most likely deficient? Prothrombin time (PT)17 seconds11-15 seconds Partial thromboplastin time (PTT)31 seconds25-37 seconds Thrombin time (TT)16 seconds15-21 seconds
factor VII
Which of the following single-factor inherited deficiencies is most common as the cause for hemophilia?
factor VIII
A 39-year-old male patient shows evidence of poor wound healing and a history of joint bleeding. What protein deficiency is most likely present?
factor XIII
The urea solubility test is used to detect deficiencies in which factor?
factor XIII
Select the next best test to run given the following PTT results on a patient's plasma: Initial PTT:75 seconds Immediate 1:1 mix with normal plasma: 38 seconds Incubated 1:1 mix with normal plasma:36 seconds
factor assays
Which of the following is decreased in DIC?
fibrinogen
All of the following can mask a deficiency of VWF and thus of type 1 VWD except
fibrinogen levels
Two children in the same family have recurrent, chronic bruising in multiple sites, repeated long-lasting epistaxis, and minor bleeding after dental work. Which type of disorder is most likely?
generalized, congenital, systemic
A 4-year-old child becomes very sick after eating undercooked ground beef. Kidney function tests are very elevated. Thrombocytopenia is mild, and a few schistocytes are noted on the blood film. Which of the following is most likely diagnosis?
hemolytic uremic syndrome
Which of the following is a commonly used drug that can cause thrombocytopenia?
heparin
An enzyme-linked immunosorbent assay (ELISA) with platelet factor 4 (PF4) coated to the surface of microplate wells is used for the diagnosis of
heparin-induced thrombocytopenia.
All of the following are associated with an increased risk of thrombosis except
high high-density lipoprotein (HDL) cholesterol
Which of the following is true concerning age-related changes of hemostasis in older adults?
increased fibrinogen
Clot-based mixing studies and Bethesda titers are used to test for
inhibitors (antibodies) against coagulation factors
Clopidogrel (Plavix) is a drug used therapeutically for patients with a risk of arterial thrombi because it
inhibits platelet function.
A normal 3-month-old boy has a hemoglobin of 11.2 g/dL. Which of the following is true about his hemoglobin? It is
lower than that of an adult of the same age.
A 37-year-old female patient has a PTT of 76 seconds (reference range, 25 to 37 seconds). Her plasma is mixed 1:1 with normal plasma. An immediate PTT performed on the mix is 74 seconds. Which of the following is the most likely diagnosis?
lupus anticoagulant
Why does the factor V Leiden mutation increase thrombotic risk?
makes factor Va resistant to degradation by activated protein C
What kind of antibody causes neonatal alloimmune thrombocytopenia?
maternal antibody against a fetal platelet antigen inherited from the father
What are the primary roles of VWF?
mediates platelet adhesion and carrier molecule for factor VIII
Which of the following results in ineffective thrombopoiesis?
megaloblastic anemia
A patient who is not on heparin and has no history of a factor deficiency has a prolonged partial thromboplastin time (PTT). Select the test that should be performed next.
mixing studies for lupus anticoagulant
Which patient group is most susceptible to bleeding because of a deficiency of vitamin K-dependent proteins?
newborns
What is believed to be the cause for acute immune thrombocytopenia purpura in children?
nonspecific binding of immune complexes to the platelet membrane after a viral illness
A patient has a quantitative D dimer of 800 ng/mL. Which can be ruled out from the following list?
patient is normal
Which of the following is normal in a patient regularly taking aspirin?
platelet count
The bleeding associated with renal disease is related most to defective
platelets
A 23-year-old man is brought by helicopter to a major trauma center after a severe motorcycle accident. He has major abdominal trauma, including a ruptured spleen, and is taken to surgery, where his spleen is removed. Two weeks after surgery, his platelet count peaks at 950 × 109/L. What is the most likely cause for this high platelet count?
postsplenectomy thrombocytosis
Which of the following age groups normally has the lowest mean red cell values (red cell count, hemoglobin, hematocrit)?
preterm premature
Which of the following would be appropriate initial testing for the siblings in Question 1?
prothrombin time (PT), partial thromboplastin time (PTT), and platelet count
A patient has a platelet count of 650 × 109/L. The other hematology tests are normal. No evidence of hemostasis failure exists. Which of the following is most likely?
reactive thrombocytosis
What is the purest form of factor VIII that is available for treating a bleeding patient with hemophilia A?
recombinant factor VIII concentrate
Which of the following is an expected finding in DIC?
schistocytes on the blood film
A 78-year-old patient recently noticed dark blotches on his forearms and on the backs of his hands. He seems to bruise even when a phlebotomy is performed using excellent technique with no problems encountered. No other symptoms exist, and all laboratory tests are normal. Which of the following is the most likely diagnosis?
senile purpura
What is the typical clinical picture in patients with severe hemophilia A?
serious anatomic bleeds into joints
What is the best test to distinguish hemophilia A from B or C?
specific factor assays
Which of the following is an example of a quantitative platelet disorder related to distribution?
splenomegaly
The qualitative platelet disorders and vascular disorders typically exhibit what type of symptoms?
superficial bleeding
What is the single most common cause of clinically important bleeding?
thrombocytopenia
What is or are the possible mechanism (or mechanisms) for bleeding in patients with severe liver disease?
thrombocytopenia inadequate production of procoagulants disseminated intravascular coagulation (DIC) all of the above
What is the correct term to describe a platelet count of 550 × 109/L when all other complete blood count (CBC) results are basically normal?
thrombocytosis
Inappropriate formation of platelets or fibrin clots that obstructs blood vessels is called
thrombosis
A 35-year-old woman with neurologic symptoms presents with a markedly decreased platelet count. She has moderate anemia with many red cell fragments on the blood film, as well as polychromasia and nucleated red blood cells (RBCs). The prothrombin time (PT) and partial thromboplastin time (PTT) are both normal. Which of the following is most likely diagnosis?
thrombotic thrombocytopenic purpura
Which of the following is successfully treated with plasmapheresis?
thrombotic thrombocytopenic purpura
Which is the most common form of von Willebrand disease (VWD)?
type 1
The terms petechiae, purpura, and ecchymoses all describe
varying size hemorrhages into the skin because of small-vessel bleeding.
Which of the following is more likely to result from poor absorption than from inadequate nutritional intake in older adults?
vitamin B12 deficiency