What is analysed?
The coagulation cascade is the activation of clotting factors (proteins) in a sequence when blood clotting tests are performed.
What does the result mean?
The result provides insights into the blood clotting process, specifically focusing on the series of events that lead to the formation of a blood clot.
Why conduct the analysis?
The coagulation cascade test is conducted to diagnose bleeding disorders such as haemophilia and liver diseases. The analysis is also conducted before surgical procedures to assess the patient’s blood clotting ability and assess the risk of thrombosis.
When to conduct the analysis?
The coagulation cascade is conducted when symptoms of bleeding disorders, such as unexplained bruising or heavy bleeding, are observed. The test is also conducted prior to elective surgical procedures.
What sample is required?
A blood sample is required for the coagulation cascade test. The blood is obtained from a vein, usually in the arm.
Is any prior preparation necessary?
Patients should fast for 8-12 hours before the blood sample is taken. In addition, patients should also inform a healthcare professional about any medications being taken, as they could affect results.
How is it performed?
The sample is sent to a laboratory, where it is analysed using substances that start the clotting process. The time it takes for the sample to begin clotting is measured.
Common techniques to measure the activity of the clotting factors include:
- The prothrombin time (PT)
- The activated partial thromboplastin time (aPTT)
What are the normal values?
Test
Normal range
PT
11 to 13.5 seconds
aPTT
25 to 35 seconds
What does having altered values mean?
- Prolonged PT: Indicates bleeding disorders of the clotting factors I, II, V, VII or X, or vitamin K deficiency.
- Prolonged aPTT: Indicates bleeding disorders of the clotting factors VIII, IX, XI or XII.