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Pt vs. Ptt: What's the Difference?

Edited by Janet White || By Harlon Moss || Updated on October 10, 2023
PT and PTT are both blood tests, with PT measuring the time it takes blood to clot in the extrinsic pathway, and PTT measuring the intrinsic and common pathways.

Key Differences

PT, or Prothrombin Time, is a diagnostic blood test commonly used to evaluate the extrinsic pathway of coagulation. This test can be particularly helpful for diagnosing conditions like Vitamin K deficiency or the efficiency of blood-thinning medications. PTT, on the other hand, stands for Partial Thromboplastin Time and measures the intrinsic and common pathways of coagulation.
PT and PTT are both critical for assessing the blood's ability to clot, but they target different clotting pathways. PT primarily focuses on the factors I, II, V, VII, and X, which are part of the extrinsic system. Meanwhile, PTT evaluates factors of the intrinsic and common systems, which include factors I, II, V, VIII, IX, X, XI, and XII.
Doctors might order both PT and PTT tests to get a comprehensive picture of a patient's coagulation profile. If the PT is prolonged, it suggests a problem with the factors in the extrinsic and common pathways. However, a prolonged PTT indicates issues in the intrinsic and common pathways.
It's essential to understand that while both PT and PTT are tests related to coagulation, they provide different insights. PT is often monitored when patients are on medications like warfarin, whereas PTT is closely watched when patients are on drugs like heparin.

Comparison Chart

Pathway Measured

Intrinsic and Common

Factors Evaluated

I, II, V, VII, X

Commonly Monitored For

Warfarin therapy
Heparin therapy

Main Use

Evaluating Vitamin K deficiency or effectiveness of certain anticoagulants
Assessing unexplained bleeding or clotting disorders


Shorter (usually seconds)
Longer (also in seconds but typically longer than PT)

Pt and Ptt Definitions


PT denotes Pacific Time, a time zone.
The meeting starts at 3 PM PT.


PTT can indicate Percutaneous Tendon Transfer in medicine.
The doctor suggested a PTT to restore function in the paralyzed hand.


PT refers to Prothrombin Time, a blood test.
The patient's PT levels are within the normal range.


PTT in chemistry refers to para-Toluenethiol.
We utilized PTT as a reagent in our recent experiment.


PT can also mean Physical Therapy.
She's been attending PT sessions post her knee surgery.


PTT signifies Partial Thromboplastin Time, a blood test.
His PTT values were elevated, indicating a clotting issue.


PT stands for Personal Trainer in fitness.
My PT designed a unique workout plan for me.


PTT can refer to Push-to-Talk in telecommunications.
Use the PTT button on your walkie-talkie to communicate.


PT in the automotive world means "Pint."
The engine needs a PT of oil.


PTT is also known as the Post and Telegraph Telephone company in some countries.
PTT is the national postal service of Turkey.


Initialism of physical training, a physical education class in grade school.


(countable) point


(countable) part


Abbreviation of patient


A heavy precious metallic element; gray-white and resistant to corroding; occurs in some nickel and copper ores and is also found native in some deposits


When might a doctor order a PTT test?

A doctor might order a PTT test to evaluate unexplained bleeding or clotting disorders.

Why is PT ordered?

PT is ordered to assess the extrinsic clotting pathway, especially when patients are on warfarin.

What does PT stand for in medical terms?

PT stands for Prothrombin Time.

What does PTT assess?

PTT assesses the intrinsic and common pathways of coagulation.

Which test is longer, PT or PTT?

PTT is typically longer than PT.

How are PT and PTT values interpreted?

Elevated values can suggest a clotting problem, while lower values might indicate a risk of excessive clotting.

Outside of medicine, what does PT stand for?

PT can also mean Physical Therapy, Personal Trainer, Pacific Time, and more.

Are both tests used together?

Yes, PT and PTT are often ordered together to get a comprehensive coagulation profile.

Can PTT be used in telecommunications?

Yes, PTT can stand for Push-to-Talk in telecom.

Which test evaluates factor VII?

PT evaluates factor VII.

Which factors does PTT assess?

PTT evaluates factors I, II, V, VIII, IX, X, XI, and XII.

What might cause a prolonged PT?

Causes could include Vitamin K deficiency, liver disease, or the effect of certain anticoagulant medications.

What's the normal range for PT?

The normal range varies but is typically between 10 to 14 seconds.

How about the normal range for PTT?

The normal range for PTT is usually between 25 to 35 seconds, but it can vary based on the lab and reagents used.

When is PT commonly monitored?

PT is monitored when patients are on medications like warfarin.

Which test is more comprehensive, PT or PTT?

Both are comprehensive for their respective pathways, but they provide insights into different parts of the clotting system.

Is PT related to INR?

Yes, INR (International Normalized Ratio) is derived from the PT and is used to monitor warfarin therapy.

Are PT and PTT the same?

No, PT and PTT are different tests measuring different clotting pathways.

Can a prolonged PTT indicate hemophilia?

Yes, hemophilia can cause a prolonged PTT.

Is PTT influenced by heparin therapy?

Yes, PTT is closely watched when patients are on drugs like heparin.
About Author
Written by
Harlon Moss
Harlon is a seasoned quality moderator and accomplished content writer for Difference Wiki. An alumnus of the prestigious University of California, he earned his degree in Computer Science. Leveraging his academic background, Harlon brings a meticulous and informed perspective to his work, ensuring content accuracy and excellence.
Edited by
Janet White
Janet White has been an esteemed writer and blogger for Difference Wiki. Holding a Master's degree in Science and Medical Journalism from the prestigious Boston University, she has consistently demonstrated her expertise and passion for her field. When she's not immersed in her work, Janet relishes her time exercising, delving into a good book, and cherishing moments with friends and family.

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