Hemostasis Review Flashcards
(153 cards)
1
Q
Vasocontriction, platelet adhesion, and platelet aggregation to form hemostatic plug at the injury site occur in which stage of hemostasis?
A
Primary hemostasis
2
Q
Interaction of coagulation factors to produce fibrin and fibrin stabilization by factor XIII occur in which stage of hemostasis?
A
Secondary hemostasis
3
Q
What forms the primary hemostatic plug?
A
aggregated platelets at the injury site
4
Q
What forms the secondary hemostatic plug?
A
the production of fibrin from interaction of coagulation factors
5
Q
The release of tissue plasminogen activator, conversion of plasminogen to plasmin, and the conversion of fibrin to fibrin degradation products occurs in which stage of hemostasis?
A
Fibrinolysis
6
Q
Thrombocytopenia is what type of platelet disorder?
A
quantitative
7
Q
Decreased production and increased destruction of platelets explains which quantitative platelet disorder?
A
thrombocytopenia
8
Q
What are some disorders/syndromes that can cause decreased platelet production?
A
aplastic anemia, myelodysplastic syndromes
9
Q
What are some disorders/syndromes that can cause an increased destruction of platelets?
A
immune thrombocytopenic purpura, DIC, mechanical destruction by artificial heart valves, drugs
10
Q
The dilution effect that can cause thrombocytopenia can be explained by what event?
A
massive transfusion
11
Q
If platelet counts reach less than 30,000, what clinical manifestations may be present?
A
petechiae, menorrhagia, spontaneous bruising
12
Q
If platelet counts decrease to less than 10,000, what clinical manifestation may occur?
A
severe spontaneous bleeding
13
Q
If a thrombocytopenia patient came in with petechiae, menorrhagia, and/or spontaneous bruising, you can suspect their platelet level to be…
A
less than 30,000
14
Q
If a thrombocytopenia patient manifests with spontaneous, severe bleeding, you can suspect their platelet levels to be…
A
less than 10,000
15
Q
Which qualitative platelet disorder can be explained by the unregulated production of megakaryocytes in the bone marrow?
A
Primary thrombocytosis
16
Q
What are some disorders that can cause primary thrombocytosis?
A
essential thrombocythemia, other myeloproliferative disorders
17
Q
What would the lab tests look like for a patient with primary thrombocytosis?
A
> 1,000,000 PLT with possible abnormal platelet aggregation
18
Q
Which quantitative platelet disorder can be explained by increased platelets due to another condition?
A
secondary (reactive) thombocytosis
19
Q
What would be the suspected platelet count or a patient with secondary thrombocytosis?
A
<450,000, but less than 1,000,000
20
Q
What events can cause secondary thrombocytosis?
A
hemorrhage, surgery, splenectomy
21
Q
Bernard-Soulier syndrome is what type of platelet disorder?
A
qualitative
22
Q
Glanzmann’s thrombasthenia is what type of platelet disorder?
A
qualitative
23
Q
Delta-storage pool disorder is what type of platelet disorder?
A
qualitative
24
Q
Which qualitative platelet disorder can be explained by the lacto of functional GPIb/IX/V on platelet surface that prevents interaction with vWF, resulting in abnormal platelet adhesion to collagen?
A
Bernard-Soulier syndrome
25
Giant platelets with dense granules and increased closure time (PFA) can be seen in which qualitative platelet disorder?
Bernard-Soulier syndrome
26
Which aggregation study will be abnormal in Bernard-Soulier syndrome?
ristocetin
27
Which qualitative platelet disorder can be explained by the deficiency or abnormality of platelet membrane GPIIb/IIIa, resulting in fibrin unable to attach to platelet surface and initiate platelet aggregation?
Galzmann's thrombasthenia
28
Glanzmann's thrombasthenia will have which abnormal aggregation studies?
ADP, collagen, epinephrine
29
Which qualitative platelet disorder is cause by the deficiency of dense granules, resulting in lack of ADP release?
Delta-storage pool disorder
30
Delta-storage pool disorders will have which abnormal aggregation studies?
ADP and epinephrine in the secondary aggregation
31
List a few functional platelet disorders that can cause an acquired qualitative platelet disorder.
chronic renal failure, myeloproliferative disorders, cardiopulmonary bypass, use of aspirin and other drugs
32
What is the method for platelet aggregation studies?
Aggregating agent (ADP, collagen, ristocetin, epinephrine) is added to a platelet suspension. As platelets aggregate, there is an increase in light transmittance and platelet aggregation curved are generated. Time vs. % transmittance
33
What is the clinical significance of platelet aggregation studies?
abnormal curves are seen with qualitative platelet disorders
34
What is the method for platelet function assay (PFA)?
Citrated blood is drawn through a capillary tube coated with ADP/collagen or epinephrine/collagen. Platelets adhere and aggregate when exposed to collagen.
Closure time = length of time for platelet plug formation and close aperture of capillary tube
35
PFA replaces which test?
bleeding time
36
What is the method for the vWF:Ag test?
Immunologic test using monoclonal antibodies to vWF
37
What is the clinical significance of vWF:Ag?
vWF connects platelets to collagen.
A decrease is seen in vWD, so platelets don't function normally
38
Coagulation factor I is named...
fibrinogen
39
Factor I is in which pathway?
intrinsic, extrinsic, and common
40
What converts Factor I into fibrin?
thrombin
41
Factor II is named...
prothrombin
42
Prothrombin is in which pathways?
V
43
Which factor is the precursor of thrombin?
Factor II
44
What is the name of Factor III?
Tissue factor (TF)
45
Factor III in in which pathway?
extrinsic
46
What is tissue factor (TF)?
phospholipid released from injured vessel walls
47
What is the name of factor IV?
Calcium
48
Factor IV is in which coagulation pathways?
intrinsic, extrinsic, and common
49
Which anticoagulant binds Factor IV?
sodium citrate
50
What is the name of Factor V?
labile factor (proaccelerin)
51
Which pathways contain Factor V?
intrinsic, extrinsic, and common
52
What is the name of Factor VII?
Stabile factor (proconvertin)
53
Factor VII is in which pathway?
extrinsic
54
Factor VIII is named...
Antihemophilic factor
55
What is the most common inherited coagulation defieciency disorder (general sense)?
hemophilia
56
Antihemophilic factor is in which pathway?
intrinsic
57
Which factor circulates in association with vWF and is extremely labile?
Factor VIII
58
Which factor deficiency is responsible for hemophilia A?
Factor VIII
59
Factor IX is named...
Christmas factor (plasma thromboplastin component)
60
Factor IX is in which pathway?
intrinsic
61
Which factor deficiency is responsible for hemophilia B?
Factor IX
62
What is the name for Factor X?
Stuart factor
63
Factor X is in which pathway?
intrinsic, extrinsic, and common
64
What is the name for Factor XI?
Plasma thromboplastin antecedent
65
Factor XI is seen in which pathway?
intrinsic
66
Which factor is named the Hageman factor?
Factor XII
67
Which factor is activated by glass?
Hageman factor (XII)
68
What is the name for Factor XIII?
fibrin stabilizing factor
69
Which factor stabilizes the fibrin clot?
Factor XIII
70
What is the name for Factor HMWK?
Fitzgerald factor (high molecular weight kininogen)
71
HMWK is in which pathway?
intrinsic
72
What is the name for Factor PK?
Fletcher factor (prekallikrein)
73
Prekallikrein is part of which pathway?
intrinsic
74
What term describes a substance changed by an enzyme?
substrate
75
What factor(s) is a substrate?
Fibrinogen
76
What term describes a protein that accelerates enzymatic reactions, but has no enzymatic activity of its own?
cofactor
77
What factor(s) is cofactors?
V is a cofactor for Xa
VIII is a cofactor for IXa
78
What term describes a protein that catalyzes a change in a specific substrate?
enzyme
79
Which factor(s) is an enzyme?
serum proteases: thrombin (IIa), VIIa, IXA, XIa, XIIa, an prekallikrein
transglutimase: XIIIa
80
Where are coagulation factors produced?
liver
81
What are the vitamin K dependent factors?
II, VII, IX, and X
82
Coumadin (warfarin) affects which factors?
Vitamin K dependent factors (II, VII, IX, and X)
83
Which drug is a vitamin K antagonist?
Coumadin (warfarin)
84
[patient PT/mean normal PT]^ISI = ?
INR (international normalized ratio)
85
What is the purpose of Prothrombin time (PT)?
detect deficiencies in the extrinsic and common pathway
86
Which test is used to monitor Coumadin (warfarin) therapy?
PT
87
What is the purpose of the Activated partial Thromboplastin Time (APTT)?
Detect deficiencies in the intrinsic and common pathways
88
Which test is used to monitor unfractionated heparin therapy?
APTT
89
What would the PT and APTT results be if there was a possible deficiency of factor VII?
PT - prolonged
| APTT - normal
90
What would the PT and APTT results be if there was a possible deficiency of factors HMWK, PK, XII, XI, X, IX, and/or VIII?
PT: normal
APTT: prolonged
91
What would the PT and APTT results be if there was a possible deficiency of factors X, V, II, and/or I?
PT and APTT: prolonged
92
What test should be performed if there is an abnormal PT or APTT?
mixing studies
93
How is a mixing study performed?
mixing a 1:1 ratio of normal plasma and patient plasma
94
How is are mixing studies used to determine coagulation problems?
If time is corrected with addition of normal plasma, it is a factor deficiency problem.
If time is not corrected, and inhibitor is present
95
Which test measures the time required for thrombin to convert fibrinogen to fibrin?
Thrombin time (TT)
96
TT can be prolonged with..
hypo- or dysfibrinogenemia, heparin, FDPs
97
What is a test similar to TT, but is not affected by heparin?
Reptilase time
98
What is being tested when thrombin is added to dilutions of patient plasma and results are obtained from a standard calibration curve?
fibrinogen (normal: 200-400 mg/dL
99
What is the basis of Factor assays?
determine % of factor activity by the correction of PT or APTT when dilutions of patient plasma are added to factor-deficient plasma
100
What test is being performed in the patient's platelet-rich plasma is mixed with CaCl2, then the clot is placed in urea or monochloroacetic acid and incubated at 37 degees C?
Factor XIII screening test
101
During a Factor XIII screening test, how do you know if factor XIII is deficient?
the clot will dissolve within 24 hours
102
What test is used to monitor therapy with low molecular weight heparin?
Anti-Factor Xa assay
103
Name 3 of the most common inherited coagulation disorders?
vWD, Hemophilia A, Hemophilia B (Christmas Disease)
104
What is deficient in Von Willebrand Disease?
vWF
105
What is deficient in hemophilia A?
Factor VIII
106
What is deficient in hemophilia B?
Factor IX
107
Which two coagulation disorders have abnormal aggregation with ristocetin?
Bernard-Soulier disease and vWD
108
Which inherited coagulation disorder affects both sexes?
vWD
109
Which inherited coagulation disorder occurs primarily in males and is sex-linked?
Hemophilia A
110
What condition can explain a decrease in all coagulation factors?
liver disease
111
Which condition can explain a decrease in Factors II, VII, IX, and X?
Vitamin K deficiency
112
Which condition is explained by uncontrolled formation and lysis of fibrin in blood vessels?
Disseminated intravascular coagulation (DIC)
113
Fibrinogen, Factors II, V, VIII, XIII, and platelets are consumed in which condition?
DIC
114
Which condition activates plasminogen to plasmin, degrading fibrinogen, V, VIII, and XIII, resulting in no fibrin formation?
Primary fibrinolysis (fibrinogenolysis)
115
Antibodies against anticoagulants are considered...
inhibitors (circulating anticoagulants)
116
Inhibitors to which factors are the most common and why?
VIII and IX, due to replacement therapy for hemophilia A or B
117
D-Dimer and FDP are test of the...
fibrinolytic system
118
What is a D-Dimer?
a fragment that results from lysis of fibrin by plasmin
119
D-dimer is a marker for which acquired coagulation condition?
DIC (also positive with DVT, pulmonary embolism, and after lytic therapy)
120
What would the D-dimer result be in primary fibrinolysis?
negative
121
What are fibrin degradation products (FDPs)?
product of action of plasmin on fibrin or fibrinogen
122
What method is used in the D-dimer and FDP tests?
latex agglutination using antibodies against the tested substance
123
An increase in FDPs is a sign of...
fibrinolytic activity
124
Which tests can be used to differentiate between DIC and primary fibrinolysis?
Platelets: decreased in DIC, normal in fibrinolysis
D-Dimer: positive in DIC, negative in fibrinolysis
RBC morphology: Schistocytes in DIC, normal in fibrinolysis
125
What is a plasma inhibitoe that neutralizes all serine proteases, including thrombin?
Antithrombin (antithrombin III)
126
Deficiencies of antithrombin are associated with and increase risk of...
thrombosis
127
Which coagulation inhibitor inactivates Va and VIIIa?
Protein C
128
What is the cofactor for protein C?
Protein S
129
What is the most common cause of hereditary activated protein C resistance (APC)?
Factor V Leiden
130
Factor V Leiden is a mutation that makes Factor V resistant to...
activity of activated protein C
131
Which substances are a risk factor for thrombosis and recurrent spontaneous abortion?
lupus anticoagulants
132
What are antiphospholipid antibodies that interact with phospholipids in APTT reagent and prolong the time?
lupus anticoagulant
133
How are lupus anticoagulants detected?
unexplained prolongation of APTT that isn't corrected by mixing studies.
134
Coumadin inhibits...
vitamin K dependent factors
135
Unfractionated heparin catalyzes the inhibition of...
thrombin, Xa and IXa
136
Heparin catalyzes...
antithrombin
137
Low molecular weight heparin catalyzes the inhibition of...
Xa
138
TRUE OR FALSE: Improper labeling a criteria to reject a specimen for coagulation testing.
TRUE
139
TRUE OR FALSE: A specimen for coagulation testing should be rejected if there is a delay in delivery to the lab.
TRUE
140
TRUE OR FALSE: Exposure to extremes of temperatures is not a justified criteria to reject a coagulation sample.
FALSE
141
TRUE OR FALSE: A tube >90% full is ideal for coagulation testing.
false ... want 9:1 (blood:anticoagulant) ratio
142
TRUE OR FALSE: a clotted specimen can be used in coagulation testing.
FALSE
143
TRUE OR FALSE: A hemolyzed coagulation sample should be rejected.
True
144
Which anticoagulant is ideal for coagulation testing?
3.2% sodium citrate (labile factors are preserved better)
145
What is wrong with drawing a coagulation tube after other anticoagulant tubes?
contamination with other anticoagulants can interfere
146
Why is probing to find a vein a source of error in coagulation testing?
Tissue thromboplastin activates coagulation and will falsely decrease test times
147
What will occur if there is failure to mix anticoagulant with blood immediately after obtaining the sample?
the blood will clot
148
Polycythemia (Hct >55%) will shorten or prolong coagulation testing times?
prolong
149
What must be done to avoid prolonged times due to heparin contamination from catheters or heparin locks?
flush lines with saline and discard the first 5mL drawn
150
Why must hemolyzed coagulation samples be rejected?
hemolysis can activate clotting factors and can interfere with photometric readings
151
How should coagulation samples be stored?
at room temperature in a vertical position with a stopper to prevent pH change.
152
Specimens for PT must be tested within how many hours after collection?
24 hours
153
Specimens for APPT must be tested within how many hours after collection?
4 hours
