lab testing for bleeding and thrombic disorders Flashcards
(126 cards)
1
Q
the controlled activation of coagulation factors and platelets leading to clot formation, with subsequent clot lysis, in a process that stops hemorrhage without excess clotting
A
normal hemostasis
2
Q
the initial steps in clot formation, which mostly rely on the integrity and elasticity of the vessel wall and interactions between the vessel wall, platelets, and von Willebrand factor (VWF)
A
primary hemostasis
3
Q
primary hemostasis disorders typically present with
A
mucocutaneous bleeding
petechiae
4
Q
the subsequent formation of the fibrin-based clot, which mostly relies on coagulation factors
A
secondary hemostasis
5
Q
secondary hemostasis typically present with
A
deep tissue hematomas
hemarthrosis
6
Q
= fragments of large megakaryocyte cells in the bone marrow that perform multiple tasks important to the clotting process
A
platelets
7
Q
Adherence to the damaged blood vessel wall to initiate platelet plug
Secretion of ADP, thromboxane A2 and serotonin
Initiation of thrombin formation via platelet IIb/IIIa proteins
Production of fibrin-stabilizing factor (Factor XIII)
Production of prostaglandins
A
plt function
8
Q
= components of an enzymatic cascade with sequential conversion of proenzymes (zymogens) to fully activated enzymes, which then convert other zymogens to their activated forms
A
clotting factors
9
Q
Injury to blood vessel wall induces formation of
A
prothrombin activator
10
Q
Both the extrinsic and intrinsic pathways lead to development of
A
prothrombin activator
11
Q
catalyzes the change of prothrombin to thrombin
A
pt activator
12
Q
changes fibrinogen to fibrin threads which mix with rbc plt and plasma to form blood clot
A
thrombin
13
Q
factor 1
A
fibrinogen
14
Q
factor 2
A
prothrombin
15
Q
f 3
A
tissue thromboplastin
16
Q
4
A
calcium
17
Q
5
A
proacclerin
18
Q
7
A
proconvertin
19
Q
8
A
antihemophilic factor a
20
Q
9
A
antihemophilic factor b
21
Q
factor 10
A
stuart factor
22
Q
factor 11
A
antihemophilic fator c
23
Q
12
A
hageman factor
24
Q
13
A
fibrin stabilizing factor
25
Triggered by tissue thromboplastin which is released from damaged cells in the endothelial vascular wall or outside the blood vessel
Factor VII Common Pathway
extrinsic pathway
26
Triggered by damage to the blood cells themselves or contact of the blood cells with a foreign surface
Factor XII Factor XI Factor IX (+ Factor VIII & vWF) Common Pathway
intrinsic pathway
27
Factor X (+ Factor V) Factor II Factor I (+ Factor XIII Fibrin mesh)
common pathway
28
initiated by endothelial injury
Thromboxane A2 released from platelets contribute to vasoconstriction
vessel spasm
29
von Willebrand Factor connects platelets to injured vessel wall
Glycoprotein IIb and IIIa receptors bind fibrinogen and link platelets together
formation of plt plug
30
conversion of inactive soluble fibrinogen to insoluble fibrin via coagulation cascade
Regulated by natural anticoagulants (Antithrombin II, Protein C)
blood coagulation
31
Serum is squeezed out of the clot and the edges of the vessels are joined together
clot retraction
32
fibrinolysis
Needed for permanent tissue repair
clot dissolution
33
Abnormal function of hemostasis results in
coagulopathy
34
clotting disorders
congenital
acquired
35
bleeding disorders
plt disorders
coagulation factor disorders
36
Increased platelet destruction
Decreased platelet production
thrombocytopenia
37
Disorders associated with deficiencies of multiple functional coagulation factors
Vitamin K deficiency
Disseminated intravascular coagulation (DIC)
Liver dysfunction
Warfarin/Heparin overdose
38
immune conditions of increased plt destruction
ITP
PTP
39
non-immune conditions of increased plt destruction
DIC
TTP
HUS
40
conditions of decreased plt production
tumor infiltration of bone marrow
chemo agents
aplastic anemia
41
plt funciton disorders
vwd
asprin
42
clotting disorder- activated protein C resistance
factor v leiden mutation
43
Antiphospholipid antibody syndrome
Heparin-induced thrombocytopenia (HIT)
are conditions of
clotting disorders
44
acquired hypercoagubility conditions
cancer
pregancy
45
reasons for coagulation testing
Patients with unexplained bleeding
Patients with unexplained/repeated thrombotic episodes
Patients needing surgery
Determination of surgical bleeding/clotting risk
Monitoring of patients on anticoagulation therapy
46
medications used to PREVENT blood from clotting
anticoagulant agents
47
firect vitamin K antagonist
warfarin
48
Increases anticoagulant effect of anti-thrombin III
Given IV or SubQ
Monitored with aPTT
heparin
49
Inhibits liver’s ability to utilize Vitamin K
Oral medication
Monitored with PT/INR
vitamin K antagonists
50
Factor Xa inhibition
Given IV & SubQ
No monitoring needed
low-molecular weight heparin
51
Inhibit Factor Xa or thrombin
Oral medication
No monitoring needed
direct oral anticoagulats
52
anticoagulation therapy agents
heparin
vit k antagonists
low molecular weight heparin
direct oral anticoagulants
53
secondary hemostasis tests
Prothrombin time (PT)/International normalized ratio (INR)
Partial thromboplastin time (aPTT)
Thrombin time (TT)
Reptilase time (RT)
Specific clotting factor assays
54
Testing for VWD
von Willebrand factor (VWF) antigen
Testing for platelet disorders
Platelet count
Platelet morphology
Platelet aggregation studies
primary hemostasis tests
55
hypercoagubility tests
D-dimer
Protein C
Protein S
Fibrinogen level
56
testing performed on
plasma
57
collection tube must contain
inhibitor of coagulation
58
measures the time it takes plasma to clot when exposed to tissue factor
PT
59
PT assesses what pathways
extrinsic and common
60
normal PT value
11-13 sec
61
clinical use of PT/INR
Evaluation of unexplained bleeding
Diagnosis of DIC
Baseline prior to initiating anticoagulation therapy
Monitoring of warfarin (Coumadin) therapy
Assessment of liver synthetic function
62
causes of prolonged PT
warfarin
vit k deficiency
liver disease
dic
factor deficiency
antiphospholipid antibodies
63
A measure of how much longer it takes the blood to clot when oral anticoagulation is used
INR
64
if inr is 2
blood is taking 2x as normal to clot
65
therapeutic range of coumadin/warfarin
2-3
less than 3 is inadequate protection from clotting
higher than 4 increased bleeding risk
66
when obtain baseline inr
priot to warfarin therapy
67
2nd inr
after 2-3 med doses
68
inr obtained then how often until in therapeutic range
2x weekly
69
then can decrease to
once weekly, then every other week, then monthly
70
if inr becomes sub or supra must
increase inr
71
if inr over 10
hold doeses and admin vit k
72
measures the time it takes plasma to clot when exposed to substances that activate the contact factors
Assessment of INTRINSIC & common pathways
aPTT
73
normal aPTT
25-35 seconds
74
critical value aPTT
over 70- spontaneous bleeding
75
aPTT inducations
Evaluation of unexplained bleeding
Diagnosis of DIC
Obtaining a baseline prior to initiating anticoagulation
Monitoring therapy with unfractionated heparin
76
prolonged aPTT causes
hemophilia a and b
severe liver disease
dic
vit k def
heparin therapy
77
tests ONLY the final step of fibrin clot formation (conversion of fibrinogen to fibrin)
NOT routinely performed as part of coagulation panel
TT
78
normal TT
14-19
79
TT indications
Evaluation of prolonged PT/aPTT
Evaluation of an inherited fibrinogen disorder
80
causes of prolonged TT
antigoagulants
acquired fibrinogen disorders
DIC
liver disease
81
measures the time it takes for a clot to form in a blood sample after the addition of reptilase, a snake venom enzyme with thrombin-like activity
reptilase time RT
82
normal RT
less than 20 sec
83
RT indications
Prolonged TT
Suspected congenital or acquired fibrinogen disorders
84
causes of prolonged RT
fibrinogen deficiency
heparin contamination
dysfibrinogenemia
85
tests that measure the level of individual clotting factors in the blood
specific factor assays.
86
specific factor assay indications
Prolonged PT/aPTT
Suspected factor deficiency
Monitoring treatment of factor deficiencies
Detection of INHIBITORS
87
most common individual factors assessed
factor 9 and 9
88
antibodies that neutrolize the activity of specific clotting factors
inhibitors
89
A FOLLOW-UP study if PT/INR &/or aPTT are prolonged
The patient’s plasma is mixed 50:50 with control plasma, and then the PT/INR or aPTT is repeated.
If the PT/INR &/or aPTT becomes normal = FACTOR DEFICIENCY
If the PT/INR &/or aPTT stays prolonged = INHIBITOR present
mixing studies
90
assesses overall platelet function
Measures formation of platelet plug
bleeding time
91
normal BT
2-7 min
92
BT prolonged with
Thrombocytopenia
von Willebrand's disease
Medications that impact platelet function
Aspirin
Clopidogrel (Plavix)
93
plt count
150k-400k
94
low plt count less than 15000
thrombocytopenia
95
inherited disorder characterized by deficiency or dysfunction of von Willebrand factor
MOST COMMON inherited bleeding disorder
vwd
96
subtypes of wvd
1- low levels-common
2- dysfunctional
3- complete deficiency-rare
97
AMOUNT of von Willebrand factor
vw antigen
98
functionality of von Willebrand factor
vw activity
99
one of the major fibrin degradation products released upon cleavage of crosslinked fibrin by plasmin
fibrin d-dimer
100
helps to rule out acute thrombosis
d dimer
101
Elevated concentrations of plasma D-dimer indicate
clinical suspicion of recent or ongoing intravascular coagulation and fibrinolysis
102
neg/norm d-dimer
must confirm that is no acute clot
103
pos/elev d-dimer
clinical suspicion must complete full clot work-up
104
is a key protein in blood clotting --- precursor to fibrin
fibrinogen
105
fibrinogen normal range
200-400
106
low fibrinoven levels cause
prolonged bleedine-
dic
liver disease
107
high fibrinogen levels cause
increased clot formation
-infection
-malignancy
108
is a vitamin K dependent protein that is produced by the liver and prevent thrombus formation by inactivating Factor V and Factor VIII
protein C
109
normal protein c
65-135
110
Utilized in evaluation of patients with severe thrombotic episodes
protein C levels and S
111
causes of protein c deficiency
Genetic disorder
Severe liver disease
DIC
Vitamin K deficiency
112
is a vitamin K dependent protein that acts as a co-factor to enhance the anticoagulant effects of Protein C
Normal Range – age dependent
protein s
113
causes of protein S def
Genetic disorders
Acquired:
Autoimmune disorders
Severe liver disease
DIC
Vitamin K deficiency
114
initial lab tests for bleeding disorders
Platelet count
Bleeding Time
PT/INR
aPTT
Fibrinogen level
115
vir k def patterns
increased PT/INR
increased aPTT
116
warfarin use
increased PT/INR
increased aPTT
117
hemophilia a/b
increased aPTT
118
vwd
possible increased aPTT
increased BT
119
DIC
increased PT/INR
increased aPTT
increased BT
decreased plt
120
personal and fhx of bleeding episodes
International Society of Thrombosis and Hemostasis (ISTH) Bleeding Assessment Tool
Screening of INHERITED bleeding disorders
121
PE manifestations of bleeding
Skin Bleeding
Petechiae
Ecchymoses
Purpura
Signs of liver disease
122
who to screen pre-op
Known bleeding disorder
Family history of bleeding disorder
Comorbidity likely to impair hemostasis
Surgery with a high risk of bleeding
123
initial pre-op screening lab tests
PT/INR
aPTT
Platelet count
124
surgeries high bleeding risk
neurosurgery
open cardiac surgical
major vascular surgical
125
initial lab tests for clotting disorders
Fibrinogen levels
D-dimer
Protein S levels
Protein C levels
126
follow up studies for clotting disorders
Activated Protein C Resistance Assay – measures the ABILITY of Protein C to inactivate Factor V
Direct genetic testing for Factor V Leiden mutation
