Partial Thromboplastin Time (PTT) Test

Test Overview

Partial thromboplastin time (PTT) is a blood test that measures the time it takes your blood to clot. A PTT test can be used to check for bleeding problems.

Blood clotting factorsclotting factors are needed for blood to clot (coagulation). The partial thromboplastin time is an important test because the time it takes your blood to clot may be affected by:

Blood-thinning medicine, such as heparin. Another test, the activated partial thromboplastin time (APTT) test, may be used to find out if the right dose of heparin is being used.
Low levels of blood clotting factors.
A change in the activity of any of the clotting factors.
The absence of any of the clotting factors.
Other substances, called inhibitors, that affect the clotting factors.
An increase in the use of the clotting factors.

Another blood clotting test, called prothrombin time (PT) or INR (international normalized ratio), measures other clotting factors. Partial thromboplastin time and prothrombin time are often done at the same time to check for bleeding problems caused by a problem with the clotting factors.

Why It Is Done

Partial thromboplastin time (PTT) is done to:

Find a cause of abnormal bleeding or bruising.
Check for low levels of blood clotting factors. The lack of some clotting factors can cause bleeding disorders such as hemophiliahemophilia.
Check for conditions that cause clotting problems. Conditions such as antiphospholipid antibody syndrome or lupus anticoagulant syndrome develop when the immune system makes antibodiesantibodies that attack blood clotting factors. This can cause the blood to clot easily in veins and arteries.
Check if it is safe to do a procedure or surgery that might cause bleeding.
Check how well the liver is working.

The activated partial thromboplastin time (APTT) test is used after you take blood-thinners to see if the right dose of medicine is being used. If the test is done for this purpose, an APTT may be done every few hours. When the correct dose of medicine is found, you will not need so many tests.

How To Prepare

How It Is Done

How It Feels

Risks

Results

Normal

Each lab has a different range for what's normal. Your lab report should show the range that your lab uses for each test. The normal range is just a guide. Your doctor will also look at your results based on your age, health, and other factors. A value that isn't in the normal range may still be normal for you.

Abnormal values

A longer-than-normal PTT or APTT can mean a lack of or low level of one of the blood clotting factors or another substance needed to clot blood. This can be caused by bleeding disorders, such as hemophiliahemophilia or von Willebrand's diseasevon Willebrand's disease.
A longer-than-normal PTT or APTT can be caused by liver disease, kidney disease (such as nephrotic syndromenephrotic syndrome), or treatment with blood thinnersblood thinners.
A longer-than-normal PTT may be caused by conditions such as antiphospholipid antibody syndrome or lupus anticoagulant syndrome. These conditions happen when the immune system makes antibodiesantibodies that attack blood clotting factors. This can cause the blood to clot easily in veins and arteries.
The PTT can get longer when you are using heparin, so your PTT value needs to be closely checked. If you have a longer PTT, you may have a higher risk of bleeding.

Current as of: October 7, 2024

Author: Ignite Healthwise, LLC StaffIgnite Healthwise, LLC Staff

Clinical Review BoardClinical Review Board
All Ignite Healthwise, LLC education is reviewed by a team that includes physicians, nurses, advanced practitioners, registered dieticians, and other healthcare professionals.

This information does not replace the advice of a doctor. Ignite Healthwise, LLC, disclaims any warranty or liability for your use of this information. Your use of this information means that you agree to the Terms of UseTerms of Use. Learn how we develop our contenthow we develop our content.

To learn more about Ignite Healthwise, LLC, visit webmdignite.comwebmdignite.com.

Page Footer

I want to...

Audiences

Secure Member Sites

The Cigna Group Information

Disclaimer

Individual and family medical and dental insurance plans are insured by Cigna Health and Life Insurance Company (CHLIC), Cigna HealthCare of Arizona, Inc., Cigna HealthCare of Illinois, Inc., Cigna HealthCare of Georgia, Inc., Cigna HealthCare of North Carolina, Inc., Cigna HealthCare of South Carolina, Inc., and Cigna HealthCare of Texas, Inc. Group health insurance and health benefit plans are insured or administered by CHLIC, Connecticut General Life Insurance Company (CGLIC), or their affiliates (see a listing of the legal entities a listing of the legal entities that insure or administer group HMO, dental HMO, and other products or services in your state). Accidental Injury, Critical Illness, and Hospital Care plans or insurance policies are distributed exclusively by or through operating subsidiaries of Cigna Corporation, are administered by Cigna Health and Life Insurance Company, and are insured by either (i) Cigna Health and Life Insurance Company (Bloomfield, CT); (ii) Life Insurance Company of North America (“LINA”) (Philadelphia, PA); or (iii) New York Life Group Insurance Company of NY (“NYLGICNY”) (New York, NY), formerly known as Cigna Life Insurance Company of New York. The Cigna name, logo, and other Cigna marks are owned by Cigna Intellectual Property, Inc. LINA and NYLGICNY are not affiliates of Cigna.

All insurance policies and group benefit plans contain exclusions and limitations. For availability, costs and complete details of coverage, contact a licensed agent or Cigna sales representative. This website is not intended for residents of New Mexico.

Selecting these links will take you away from Cigna.com to another website, which may be a non-Cigna website. Cigna may not control the content or links of non-Cigna websites. Details Details