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Basic Clinician TrainingModule 2
TEG® Technology
Hemostasis monitoringRoutine coagulation tests: PT, aPTT
• Based on cascade model of coagulation Measure coagulation factors interaction in solution
(plasma) Determine if adequate levels of coagulation factors
are present for clot formation
• Do not reflect the roles of cells or contributions of local vascular and tissue conditions Plasma-based assays miss the impact of platelets and
platelet activation on thrombin generation. Plasma-based assays use static endpoints (e.g. fibrin
formation) - miss impact of altered thrombin generation on platelet function and clot structure.
Hemostasis monitoringTEG analysis system
• Whole blood test• Measures all phases of hemostasis: initiation through lysis• Shows the net effect of hemostatic components on blood clotting process
The TEG analyzerDescription• TEG: point of care (POC) whole blood
coagulation monitoring device Time to initial results: 4-8 minutes Time to completion (clot lysis): 45-60 minutes
• Uses activated blood to maximize thrombin generation and platelet activation in an in vitro environment Measures the hemostatic potential of the blood at
a given point in time under optimal conditions of thrombin generation
• Demonstrates the contributions and interactions of hemostatic components during the clotting process.
TEG technologyHow it works
TEG sample preparation
• Blood samples can be “modified” by adding agents to the sample
• Activator – maximizes thrombin generation and speeds up clotting time Kaolin – activates intrinsic pathway, used for
normal TEG analysis Tissue factor – specifically activates extrinsic
pathway• Heparinase – removes heparin from sample,
allows view of the underlying hemostatic status of a patient on heparin.
• Platelet activators – allows testing antiplatelet agent responsiveness and efficacy. (Module 7)
TEG sample types
• Kaolin – used for normal TEG analysis• Kaolin with heparinase – used for normal
TEG analysis when patient on heparin Compared with Kaolin-only sample (run
simultaneously) to determine reversal of heparin
Utility of the TEG
• Demonstrates all phases of hemostasis Initial fibrin formation Fibrin-platelet plug construction Clot lysis
• Identifies a balance or imbalance in the hemostatic system – between the clot forming and clot breakdown pathways Identifies likely cause(s) of bleeding Identifies likely cause(s) of thrombosis
What TEG analysis capturesTime
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TEG parameters
Identification
Definition
Thrombin formationThe R parameter - identified
Pin is stationary
Pin is engaged
Intrinsic,extrinsic,commonpathways
Initial fibrinformation
Cup rotates, pin remains stationary
Time
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Pin starts to rotate with cup
FibrinogenThe (angle) parameter - identified
Fibrinincreases
Amplitude of pin rotation increases as fibrin is generatedand cross links are formed
Pin isengaged
Time
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Platelet functionThe MA parameter - identified
Maximum amplitude (MA) of pin rotation
Amplitude of pin rotation
Time
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Platelet functionThe MA parameter - defined
Amplitude of pin rotation
• Amplitude of pin rotation depends on clot strength• Clot strength = 80% platelets + 20% fibrinogen• Platelet function influences thrombin generation and
fibrin formation relationship between R, , and MA
Maximum amplitude (MA) of pin rotation
Coagulation indexThe CI parameter - defined
• Linear combination of kinetic parameters of clot development and clot strength (R, K, angle, MA)
• Provides a global index of hemostatic status CI < -3.0: hypocoagulable CI > +3.0: hypercoagulable
FibrinolysisThe LY30 parameter - identified
Decrease in amplitude of pin rotation30 minutes after MA reached
Time
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30 min
MA
FibrinolysisThe LY30 parameter - defined
• Reduction in amplitude of pin rotation depends on extent of fibrinolysis
Decrease in amplitude of pin rotation30 minutes after MA reached
30 min
MA
TEG parameter summaryDefinitionsR Latency from the time that the blood was placed in the TEG® analyzer
until the initial fibrin formation.
K Measures the rapidity (kinetics) of fibrin build-up and cross-linking, that is, the speed of clot strengthening.
MA Maximum dynamic properties of fibrin and platelet bonding via GPIIb/IIIa; represents platelet function
G Derived from MA, represents the ultimate strength of the fibrin clot
CI Coagulation Index is linear combination of the above parameters.
LY30 LY30 measures the rate of amplitude reduction 30 minutes after MA. This measurement gives an indication of the stability of the clot.
TEG parameter summaryTime
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What does TEG report?
Clotting time
Clot kinetics
Clot strength
Platelet function
Clot stability Clot breakdown
“Normal” TEG tracingTime
Am
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30 min
Hemorrhagic TEG tracing
30 min
Prothrombotic TEG tracing
30 min
Fibrinolytic TEG tracing
30 min
Normal range
Actual value
Components of the TEG tracingExample: R
ParameterUnitsValueNormal range
TEG decision treeQualitative
TEG decision treeQuantitative
US Patent 6,787,363
Hemorrhagic
Thrombotic
Fibrinolytic
TEG tracingExample: hemorrhagic
**
**
TEG tracingExample: prothrombotic
*
* *
*
TEG tracingExample: fibrinolytic
**
Summary
• TEG technology measures the complex balance between hemorrhagic and thrombotic systems.
• The decision tree is a tool to identify coagulopathies and guide therapy in a standardized way.
Review exercises
TEG parameters
Hemostasis monitoring
Skip exercisesBegin
exercises
Exercise 1: TEG parameters
The R value represents which of the following
phases of hemostasis?a. Platelet adhesion
b. Activation of coagulation pathways and initial fibrin formation
c. Buildup of platelet-fibrin interactions
d. Completion of platelet-fibrin buildup
e. Clot lysis
Answer Next
Exercise 2: TEG parameters
Select the TEG parameters that demonstrate
kinetic properties of clot formation. (select all that
apply)
a. R
b. Angle ()
c. MA
d. LY30
e. CI
Answer Next
Exercise 3: TEG parameters
The rate of clot strength buildup is demonstrated
by which of the following TEG parameters?a. R
b. Angle ()
c. MA
d. LY30
e. CI
Answer Next
Exercise 4: TEG parameters
Which of the following TEG parameters will best
demonstrate the need for coagulation factors
(i.e. FFP)? a. R
b. Angle ()
c. MA
d. LY30
e. CI
Answer Next
Exercise 5: TEG parameters
Clot strength is dependent on which of the
hemostatic components? a. 100% platelets
b. 80% platelets, 20% fibrinogen
c. 50% platelets, 50% fibrinogen
d. 20% platelets, 80% fibrinogen
e. 100% fibrinogen
Answer Next
Exercise 6: TEG parameters
Which of the following TEG parameters
demonstrate a structural property of the clot? (select all that apply)
a. R
b. Angle ()
c. MA
d. LY30
e. CI
NextAnswer
Exercise 7: TEG parameters
Because the TEG is a whole blood hemostasis
monitor, a low MA demonstrating low platelet
function may also influence which of the
following TEG parameters?a. R
b. Angle ()
c. LY30
d. CI
e. None of the above
NextAnswer
Exercise 8: TEG parameters
Clot stability is determined by which of the following
TEG parameters?
a. R
b. Angle ()
c. MA
d. LY30
e. CI
NextAnswer
Exercise 9: TEG parameters
Which of the following conditions will provide the
information necessary to determine if heparin is the
cause of bleeding in a patient?
a. R value: Kaolin with heparinase
b. R value: Kaolin vs. Kaolin with heparinase
c. MA value: Kaolin with heparinase
d. MA value: Kaolin vs. kaolin with heparinase
NextAnswer
Exercise 10: TEG parameters
Which of the following parameters provides an indication
of the global coagulation status of a patient?
a. R
b. Angle ()
c. MA
d. LY30
e. CI
NextAnswer
Exercise 11: Hemostasis monitoring
Which of the following statements are true regarding the
PT and aPTT tests? (select all that apply)
a. Measure coagulation factor interaction in solution
b. Measure platelet contribution to thrombin generation
c. Measure influence of thrombin generation on platelet function
d. Use fibrin formation as an end point
NextAnswer
Exercise 12: Hemostasis monitoring
The TEG analyzer can monitor all phases of hemostasis
except which of the following? (select all that apply)
a. Initial fibrin formation
b. Fibrin-platelet plug construction
c. Platelet adhesion
d. Clot lysis
NextAnswer
Exercise1: TEG parameters
The R value represents which of the following
phases of hemostasis?a. Platelet adhesion
b. Activation of coagulation pathways and initial fibrin formation
c. Buildup of platelet-fibrin interactions
d. Completion of platelet-fibrin buildup
e. Clot lysis
Next
R
Exercise 2: TEG parameters
Select the TEG parameters that demonstrate
kinetic properties of clot formation. (select all that
apply)
a. R
b. Angle ()
c. MA
d. LY30
e. CI
Next
Exercise 3: TEG parameters
The rate of clot strength buildup is demonstrated
by which of the following TEG parameters?a. R
b. Angle ()
c. MA
d. LY30
e. CI
Next
Exercise 4: TEG parameters
Which of the following TEG parameters will best
demonstrate the need for coagulation factors
(i.e. FFP)? a. R
b. Angle ()
c. MA
d. LY30
e. CI
Next
Exercise 5: TEG parameters
Clot strength is dependent on which of the
hemostatic components? a. 100% platelets
b. 80% platelets, 20% fibrinogen
c. 50% platelets, 50% fibrinogen
d. 20% platelets, 80% fibrinogen
e. 100% fibrinogen
Next
Exercise 6: TEG parameters
Which of the following TEG parameters
demonstrate a structural property of the clot? (select all that apply)
a. R
b. Angle ()
c. MA (demonstrates maximum clot strength)
d. LY30 (demonstrates clot breakdown or the structural
stability of the clot)
e. CI
Next
Exercise 7: TEG parameters
Because the TEG is a whole blood hemostasismonitor, a low MA demonstrating low platelet function may also influence which of thefollowing TEG parameters?
a. R – thrombin generation occurs mainly on the surface of platelets, thus a defect in platelet function may slow the rate of thrombin and fibrin formation.
b. Angle () – a defect in platelet function may slow the rate of formation of platelet-fibrin interactions, thus slowing the rate of clot buildup.
c. LY30
d. CI
e. None of the aboveNext
Exercise 8: TEG parameters
Clot stability is determined by which of the following
TEG parameters?
a. R
b. Angle ()
c. MA
d. LY30
e. CI
Next
Exercise 9: TEG parameters
Which of the following conditions will provide the
information necessary to determine if heparin is the
cause of bleeding in a patient?
a. R value: Kaolin with heparinase
b. R value: Kaolin vs. Kaolin with heparinase
c. MA value: Kaolin with heparinase
d. MA value: Kaolin vs. kaolin with heparinase
Next
Exercise 10: TEG parameters
Which of the following parameters provides an indication
of the global coagulation status of a patient?
a. R
b. Angle ()
c. MA
d. LY30
e. CI (Coagulation index: a linear combination of the R, K, angle, and MA)
Next
Exercise 11: Hemostasis monitoring
Which of the following statements are true regarding the
PT and aPTT tests? (select all that apply)
a. Measure coagulation factor interaction in solution
b. Measure platelet contribution to thrombin generation
c. Measure influence of thrombin generation on platelet function
d. Use fibrin formation as an end point
Next
Exercise 12: Hemostasis monitoring
The TEG analyzer can monitor all phases of hemostasis
except which of the following? (select all that apply)
a. Initial fibrin formation
b. Fibrin-platelet plug construction
c. Platelet adhesion (vascular mediated event that occurs in vivo, but not in vitro)
d. Clot lysis
Next
End of Module 2
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