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Dilute Prothrombin Time (dPT) Ratio

Published: July 27, 2026Updated: August 25, 2026

The dPT ratio measures the clotting time of blood plasma after it has been diluted, assessing the effectiveness of the coagulation pathway.

Quick summary

The dPT ratio is a diagnostic tool used to evaluate blood clotting efficiency.

Medically reviewed by WellAlly Editorial TeamLast reviewed August 25, 2026Editorial policy

Key facts at a glance

Units
ratio
Clinical utility
diagnostic
Result kind
quantitative
FDA-cleared
Siemens dPTT, Stago PTT-LA
interpretation: {"text":"0–1.2 ratio: Indicates normal clotting function.","label":"Normal"}; {"text":">1.2 ratio: May indicate a clotting factor deficiency or the presence of inhibitors.","label":"Elevated"}

The dilute prothrombin time (dPT) ratio is a coagulation test that evaluates how long it takes for blood to clot after being diluted. This test helps in identifying abnormalities in the coagulation cascade, particularly in the intrinsic and common pathways.

A dPT ratio within the reference range (0–1.2) typically indicates normal clotting function. Elevated ratios may suggest deficiencies in clotting factors or the presence of inhibitors affecting the coagulation process.

This test is often used in conjunction with other coagulation tests to diagnose bleeding disorders or to monitor the effectiveness of anticoagulant therapy.

Frequently asked questions

What is the purpose of the dPT test?
The dPT test is used to evaluate the efficiency of the blood clotting process and to identify potential deficiencies or inhibitors in the coagulation cascade.
How is the dPT ratio interpreted?
A ratio within 0–1.2 is considered normal, while a higher ratio may indicate a clotting disorder or the need for further testing.
  1. 1
    Prothrombin Time TestSource
  2. 2
    Coagulation TestingSource

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This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.

Medical Disclaimer

This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.

If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.

Medically reviewed by WellAlly Editorial Team Last reviewed August 25, 2026. · Read our editorial policy