This document discusses coagulation (clotting) testing, which measures the function of blood vessels, platelets, and coagulation factors to achieve hemostasis (stopping of bleeding). It describes the principle, methodology, and clinical significance of prothrombin time testing using an automated analyzer. The prothrombin time test evaluates the extrinsic coagulation pathway and is used to monitor patients on oral anticoagulant therapy. The test involves mixing citrated plasma with tissue thromboplastin and calcium chloride, then measuring the clotting time and calculating the international normalized ratio to standardize results. Abnormal results can indicate coagulation disorders or effects of medications on clotting.

1. COAGULATION
BY ADU BASI
1

2. INTRODUCTION
•Coagulation or clotting means to stop the flow of blood by forming a clot or a process of
changing from a liquid to a gel.
•It involves; the blood vessels, blood coagulation factors, inhibitors, platelets, fibrinolytic system
as well as co-factors to achieve haemostasis.
•Coagulation studies are a group of haematologic studies that reflect the function of blood vessels,
platelets, and coagulation factors, which all work in harmony to achieve haemostasis.
•Clinician must have access to a variety of relevant tests in order to achieve a specific or correct
diagnosis.
•A blood clot is formed by a network of fibrin threads. In this network, there are trapped red blood
cells, platelets and white blood cells.
2

3. DEMONSTRATION OF COAGULATION
IN VIVO (INTRO. CONT’D)
3
Factor X- Stuart-Prower
Factor IX- Christmas
Factor XI- Plasma
Thromboplastin Antecedent
Factor XII- Hageman

4. CLINICAL SIGNIFICANCE
•It is to achieve haemostasis; (Thrombosis and haemorrhage)
•Clotting disorders can cause a dangerous amount of bleeding or clotting. Coagulation tests
measure various proteins and how they function.
•Liver disease, Thrombophilia, Haemophilia interfere with an individual’s ability to clot.
•Coagulation tests are useful in monitoring people who take medications that affect clotting ability.
Conditions that can cause coagulation problems include:
4

5. PRINCIPLE OF TEST
•To evaluate the overall efficiency of the extrinsic pathway (Prothrombin) and intrinsic pathway
(Activated prothrombin time test)
•When blood vessel walls are damaged, the blood vessels contract to slow down the blood stream.
The damaged cells from the vessel’s inner wall (endothelium) trigger several processes, including
the activation of platelets and the clotting mechanism. Activated platelets stick together
(adhesion) and form complexes (aggregation) that result in the first haemostatic plug in the vessel
wall to stop the bleeding. Activated platelets also form the surface for the clotting process.
•Clotting (coagulation) occurs through the formation of a network of fibrin, involving the 'clotting
factors' being activated. The fibrin network and the haemostatic plug form a secure solution for
stopping bleeding and give the body the opportunity to repair the blood vessel.
5

6. PRINCIPLE OF CS-1600
•The CS-1600 is equipped with an optical fibre that supplies light at 4 different wavelengths, and a
detector capable of receiving light in multiple wavelengths.
•Multi-wavelength detector for transmitted light at 405, 575, 660 and 800 nm by splitting the light
from a halogen lamp into beams
•It allows measurement of multiple parameters with varying methodologies simultaneously.
•Measurement principles (clotting, chromogenic, immunoturbidimetric) are combined in one
analyzer.
•8 channels for clotting, chromogenic and immunoassays
6

7. PREPARATION BEFORE THE TEST
•Ensuring the info on sample corresponds with patient information
•The blood obtained should be only from the veins and must be clean and atraumatic.
•The sample must be in a sodium citrate anticoagulant tube and should be introduced without
frothing.
•Preparation of platelet poor plasma (4 degrees Celcius, span at 4000rpm for 13 mins.)
•For transportation of sample, sample should be transported with crushed ice and stored at -40
degrees Celsius and thawed when needed.
7

8. REQUIRED SAMPLE AND SAMPLE
TUBE
Required sample is plasma and should be
obtained by centrifuging blood collected by
venipuncture into a blue-top tube containing 3.2%
buffered sodium citrate. (9:1)
8

9. MATERIALS NEEDED
•Water bath
•Timer
•Marker or pencil
•Sodium citrate tubes
•Calcium chloride
•Tissue thromboplastin
•Micropipette and pipette tips
•Centrifuge
•AUTOMATED ANALYSER (SYSMEX CS-1600)
9

10. METHODOLOGY (Prothrombin)
•Set water bath at 37 degree Celsius and place a glass tube in it
•Add calcium chloride (CaCl₂) another test tube and allow to warm
•Pipette 0.1ml of patient sample into test tube and add 0.1ml of tissue thromboplastin
•Allow the mixture to warm for 3minutes.
•Wick 0.1ml of pre-warmed CaCl₂ and add to patient sample.
•As soon as a clot is seen, the timer is stopped. This time indicates the prothrombin time.
•Duplicate the test for inconveniences
•Calculate the average time in seconds for patient and control
10

11. RESULTS AND ITS
INTERPRETATION
•11 to 16 seconds for prothrombin time test
•30 to 40 seconds for activated prothrombin time test
•INR (International Normalized ratio):The INR is a calculation that adjusts for changes in the PT
reagents and allows for results from different laboratories to be compared.
•ISI (International Standardized index): The International Normalized Ratio (INR)/International
Sensitivity Index (ISI) system was developed as a way to standardize the prothrombin time during
the monitoring of patients undergoing oral anti-coagulant therapy with vitamin K antagonists
11

12. SOURCES OF ERRORS
•Undetailed medical history e.g. Aplastic anaemia, thrombocytopenia
•Drugs that act as inhibitors to coagulation/oral anticoagulants
•Diseases; obstructive liver disease and vitamin K deficiency.
12

13. REFERENCES
•Haemostasis - Sysmex Europe. Available at: https://www.sysmex-
europe.com/products/diagnostics/haemostasis.html (Accessed: November 28, 2022).
•Pietrangelo, A. (2018) Coagulation tests: Types, procedure, and results, Healthline. Healthline
Media. Available at: https://www.healthline.com/health/coagulation-tests (Accessed: November
28, 2022).
•Sysmex. Available at: https://www.sysmex-ap.com/wp-content/uploads/2020/08/Sysmex_CS-
1600Bro2019_FinalLR.pdf (Accessed: November 28, 2022).
13

14. THANK YOU
14