Doctor's Assessment Included
Every result includes a professional assessment from a BIG-registered doctor. For treatment decisions, discuss your results with your GP.
PT (Prothrombin Time)
Prothrombin Time is important for coagulation and liver assessment in older adults, particularly those on anticoagulant therapy.
What It Measures
This test measures the clotting time of plasma after adding tissue factor and calcium. The result is expressed in seconds. PT evaluates the extrinsic and common clotting pathways.
Why It Matters
PT/INR is essential for warfarin monitoring, liver function assessment, and screening for clotting factor deficiencies.
When to Test
PT can be ordered before surgery, for warfarin monitoring, when liver disease is suspected, or when unexplained bleeding occurs. It is frequently ordered alongside aPTT.
Symptoms
Low Levels
A short PT may suggest a hypercoagulable state, though it is rarely clinically significant in isolation.
High Levels
A prolonged PT may indicate liver disease, vitamin K deficiency, warfarin effect, or factor deficiency. Symptoms may include easy bruising and prolonged bleeding.
Lifestyle Tips
Ensure adequate vitamin K intake through green leafy vegetables. If on warfarin, maintain consistent dietary habits and attend regular monitoring.
Frequently Asked Questions
What is the difference between PT and INR?
PT is the raw measurement in seconds. INR normalises PT across laboratories using an international standard.
Can vitamin K deficiency affect PT?
Yes. Vitamin K is essential for producing factors II, VII, IX, and X. Deficiency prolongs PT.
Why is PT important for liver assessment?
The liver produces most clotting factors. PT reflects liver synthetic function and is included in MELD and Child-Pugh scores.