TEG® 5000 Thrombelastograph® Hemostasis Analyzer system is a diagnostic instrument that provides comprehensive whole blood hemostasis testing that can help assess bleeding and thrombotic risks, and also monitor antithrombotic therapies. By providing a more complete picture of your patients' hemostasis, the TEG system can help facilitate your understanding of hemorrhagic or thrombotic risk so you can deliver more targeted treatment.Routine coagulation tests are often used as a starting place when investigating the cause of bleeding although they were not designed for this purpose. They indicate the time of fibrin formation through either the intrinsic or extrinsic pathways of the coagulation cascade. In short, they provide only a snap shot of pieces of the entire coagulation process. While standard tests like PT, PTT, and platelet count have limited capacity to reveal a patient’s risk for bleeding, they don’t provide information on the patient’s risk for thrombosis. Nor do these routine tests provide specific data about clot quality or stability. The TEG hemostasis analyzer system is designed to provide a complete analysis to help determine the right blood product or therapy at the right time to manage a patient’s risk for hemorrhage or thrombosis

1. Thromboelastography
(TEG)
VIPIN SINGH
DEPARTMENT OF BIOCHEMISTRY
INSTITUTE OF MEDICAL COLLEGE,
BHU
vipinsingh.tech@gmail.com

2. Thromboelastography (TEG) is a viscoelastic hemostatic assay
that measures the viscoelastic properties of whole blood clot
formation.
• Interaction of platelets with the coagulation cascade
(aggregation, clot strengthening, fibrin cross-linking and
fibrinolysis).
• Measures the functional ability of the blood to make a
hemostatic plug.
• Analyzes real-time blood coagulation parameters.

3. PRINCIPLE
• The principle of this in vitro
test is to detect and quantify
dynamic changes of the
viscoelastic properties of a
blood sample during clot
formation under low shear.

4. INTRUMENTATION

5. • Kaolin, an inert silicate, negatively charged particulate
activator of the intrinsic clotting pathway.
• kaolin promotes clotting by activating Factor XII, in which it
initiates the intrinsic clotting cascade via activating Factor XI
and ends with the formation of a fibrin clot.
• In addition, kaolin can also promote the activation of platelet-
associated Factor-XI to initiate the intrinsic clotting cascade
normally in Factor XII-deficient patients.
KAOLIN

6. Mechanism of instrument
• Each chamber consists of a platform with a disposable cup
where a blood sample is placed and a detection pin
suspended in its center.
• The cup oscillates around the detection pin in a limited arc
of plus or minus (+/-) 4 degrees 45' every 5 seconds.
• Induced pin movement is recorded, and changes are
measured as a function of time.

7. PROCESS (how to operate TEG)
i. Cup and pin insert in the TEG machine.
ii. E-test of instrument.
iii. 1ml of citrated blood added in kaolin vial
iv. addition of 20 uL of 0.2M calcium chloride in disposable TEG
cupand analyse graph.
v. 340 uL of blood from kaolin vial is pipetted to the TEG cup
vi. Machine in test position
vii. Initialize test for 60-90 min.

8. • Cup oscillates around submerged torsion pin
which suspended in a cup (heated to 37C) from a
torsion wire connected with a mechanical-
electrical transducer which is connected to a
computer.
• As coagulation occurs, pin adheres to clot and
begins to move with it.
• Magnitude of pin motion directly proportional
to strength of the clot.
• Pin motion is displayed graphically by the
computer. Torsion pin remains motionless until
clotting begins.

9. Parameters
R value = reaction time (s)
 time from start of test to
initial fibrin formation
(amplitude of 2mm)
 initiation phase
 dependent on clotting
factors
Prolongation of the R time
reflects deficiency of
coagulation factors that may
be corrected by fresh frozen
plasma (FFP) transfusion.

10. K = kinetics (s)
 Time taken to achieve a
certain level of clot
strength (20mm)
 Amplification phase
 Dependent on fibrinogen
Prolongation of the K time,
suggests a deficiency of
fibrinogen and may be
corrected by cryoprecipitate
or fibrinogen concentrate.

11. Alpha angle (slope of line
between R and K)
 rate of clot formation
 “thrombin burst” / propagation
phase
 dependent on fibrinogen
a decrease of the alfa angle,
suggests a deficiency of fibrinogen
and corrected by cryoprecipitate or
fibrinogen concentrate

12. MA = maximum amplitude
(mm)
• represents the ultimate
strength of the fibrin clot; i.e.
overall stability of the clot
• dependent on platelets (80%)
and fibrin (20%).
Low MA indicates a quantitative
or functional deficiency of
platelets and could be corrected
by platelet transfusion.

13. LY30 = amplitude at 30 minutes
• percentage decrease in
amplitude at 30 minutes post-
MA
• fibrinolysis phase
• clot lysis time(CLT) (s)
an increased LY value implies
activated fibrinolysis that may be
treated by fibrinolysis inhibitors
(aminocaproic or tranexamic
acid).

14. Approximate normal values
 R: 4-8 min
 K: 1-4 min
 α-Angle: 47-74°
 MA: 55-73mm
 LY 30%: 0-8%

16. Diseased Analysis
with
TEG

17. HAEMOPHILIA

18. Thrombocytopenia
/low platelet count

19. HYPERCOGULATION

20. HYPOCOGULATION

21. Modifications of the classic TEG
 Rapid TEG (r-TEG) utilizes tissue factor instead of the kaolin
reagent to activate blood coagulation.
 Because tissue factor triggers the extrinsic coagulation
pathway, which involves a smaller number of coagulation
factors, So this test can be performed faster than conventional
TEG.
 Rapid TEG can be completed within 15 minutes.
 heparinase TEG (hTEG) measures the effect of heparin
reversal on blood coagulation.

22. ROTEM® (from Germany)
• ROTEM® has an immobile cup
wherein the pin/wire transduction
system slowly oscillates (±4°45′every
6s).
• In this assay, some different activator
reagents are utilized to investigate
specific components of the
coagulation pathway.
• ROTEM® is more resistant to
mechanical shock, which may be an
advantage in the clinical setting.

23. Equivalent variables for ROTEM®
Clotting time (CT) = R time
Clot formation time (CFT) = K value
Maximum clot firmness (MCF) = Maximum amplitude (MA)
Clot lysis (CL) = LY30

24. TEG6s
This newer machine no longer uses the ‘pin-in-cup’ technique
(as did its TEG-5000)
• It uses ‘resonance’ where blood is exposed to a fixed
vibration frequency range
• The detector measures motion of blood meniscus under LED
illumination and transforms that movement into tracing of
clot dynamics.
• With pre-prepared cartridges, there is no longer any
pipetting required!

25. Advantage
• The main advantage of TEG testing is its potential to deliver
immediate goal-oriented and individualized care to a bleeding
patient.
• Global assessment of blood coagulability, including
coagulation cascade, platelet function, and fibrinolysis
• Rapid real-time
• simple methodology & easy to handle.
• Guide transfusion therapy
• Predict the clinical efficacy of therapeutic agents affecting
blood coagulability.
The overall goal of the TEG® system is to reduce thrombotic
complications leading to improved patient outcomes.

26. Clinical Significance
• The main advantage of TEG testing is its potential to deliver
immediate goal-oriented and individualized care to a bleeding
patient.
• TEG has been used to predict early transfusion requirements
of trauma patients
• predict bleeding after cardiac surgery, kaolin-activated TEG
was demonstrated to be more useful.
• Predict the clinical efficacy of therapeutic agents affecting
blood coagulability.

27. Limitations
TEG measures blood coagulation in vitro, with or without an
additional activator.
• Blood coagulation also depends on the size of the injured
vessel, blood flow characteristics, and local vessel wall biology
that determines the quantity and functional activity of the
membrane-bound coagulation factors.
TEG has a sensitivity and specificity that may vary significantly in
different populations.

28. • Patients taking anticoagulants and antiplatelet agents are a
major concern in the trauma setting.
Ex. Warfarin is a commonly prescribed medication that has been
associated with increased mortality in trauma patients. In about
half of patients on warfarin therapy, R-time may be normal in
TEG.
This is a good example of how TEG may miss a clinically
significant coagulopathic state.

29. Clinical Guidelines
• NICE guidelines recommend thromboelastography to help
detect, manage and monitor hemostasis in cardiac surgery
patients.
• Other clinical guidelines do not currently strongly recommend
TEG for use in other settings due to the lack of high-quality
evidence.

30. Thank you