Chernecky CC, Berger BJ. Bleeding time, ivy - blood. In: Chernecky CC, Berger BJ, eds. Laboratory Tests and Diagnostic Procedures. 6th ed. Philadelphia, PA: Elsevier Saunders; 2013:181-266. Show
Pai M. Laboratory evaluation of hemostatic and thrombotic disorders. In: Hoffman R, Benz EJ, Silberstein LE, et al, eds. Hematology: Basic Principles and Practice. 7th ed. Philadelphia, PA: Elsevier; 2018:chap 129. Schafer AI. Approach to the patient with bleeding and thrombosis. In: Goldman L, Schafer AI, eds. Goldman-Cecil Medicine. 26th ed. Philadelphia, PA: Elsevier; 2020:chap 162. Because of other tests, it has lost its importance. Clotting time was done by the Lee-white method, but it was cumbersome, insensitive, and nonreproducible.Definition of clotting time (CT)Clotting time (CT) is the time that is required to form the clot. The most commonly used test of clotting time is activated partial thromboplastin time (APTT) and prothrombin time (PT). This test measures how long it takes your blood to clot. It's often used to check how well a medicine called heparin is working. Heparin slows the ability of blood to clot, and the ACT test helps your healthcare provider find the right dosage. This test uses whole blood, which is different from the standard tests for coagulation. Those tests use plasma. Plasma is blood that has had the red cells, white cells, and platelets removed. The ACT test is usually used during procedures when results may be needed right away. Why do I need this test?You may need this test if you are getting heparin to prevent your blood from clotting during a procedure such as open heart surgery, cardiac catheterization, or kidney dialysis. This test is usually done in the hospital at your bedside. What other tests might I have along with this test?You may have other blood tests to measure how quickly your blood clots. A blood test called activated partial thromboplastin time (APTT) is often done as a backup to the results of the ACT test. What do my test results mean?Test results may vary depending on your age, gender, health history, and other things. Your test results may be different depending on the lab used. They may not mean you have a problem. Ask your healthcare provider what your test results mean for you. This test doesn't measure the amount of heparin in your blood. It measures only how long it takes for a blood clot to form. The results are given in the number of seconds:
The therapeutic range is usually about double the normal clotting time. It's important to be in this range because if your ACT is too low, you may be in danger of a blood clot forming during a procedure. Some procedures may require an even longer ACT. If your ACT is too high, you may be in danger of bleeding. How is this test done?The test requires a blood sample, which is drawn through a needle from a vein in your arm. Does this test pose any risks?Taking a blood sample with a needle carries risks that include bleeding, infection, bruising, or feeling dizzy. When the needle pricks your arm, you may feel a slight stinging sensation or pain. Afterward, the site may be slightly sore. What might affect my test results?Many things may affect your lab test results. These include the method each lab uses to do the test. Even if your test results are different from the normal value, you may not have a problem. To learn what the results mean for you, talk with your healthcare provider.
Other factors that may affect your results include:
How do I get ready for this test?You don't need to prepare for this test. But be sure your healthcare provider knows about all medicines, herbs, vitamins, and supplements you are taking. This includes medicines that don't need a prescription and any illegal drugs you may use. The prothrombin time, sometimes referred to as PT or pro time, test is a test to evaluate blood clotting. Prothrombin is a protein produced by your liver. It is one of many factors in your blood that help it to clot appropriately. Products & Services
Why it's doneMost often, the prothrombin time is monitored if you are taking the blood-thinning medication warfarin. In this situation, the prothrombin time is shown as an international normalized ratio (INR). Your health care provider may recommend a prothrombin time test before surgery if there is any concern about your blood's ability to clot. The prothrombin time test also may be performed to check for liver disease. It is one of many tests used to screen people waiting for liver transplants. That screening — known as the model for end-stage liver disease (MELD) — is a scoring system for assessing the severity of chronic liver disease. If your provider suspects you have other health issues, such as liver problems or a bleeding disorder, you might need more testing to confirm your condition. Request an Appointment at Mayo Clinic There is a problem with information submitted for this request. Review/update the information highlighted below and resubmit the form. From Mayo Clinic to your inboxSign up for free, and stay up to date on research advancements, health tips and current health topics, like COVID-19, plus expertise on managing health. ErrorEmail field is required ErrorInclude a valid email address Learn more about Mayo Clinic’s use of data.To provide you with the most relevant and helpful information, and understand which information is beneficial, we may combine your email and website usage information with other information we have about you. If you are a Mayo Clinic patient, this could include protected health information. If we combine this information with your protected health information, we will treat all of that information as protected health information and will only use or disclose that information as set forth in our notice of privacy practices. You may opt-out of email communications at any time by clicking on the unsubscribe link in the e-mail. What is the normal time of blood clot?The average time range for blood to clot is about 10 to 13 seconds. A number higher than that range means it takes blood longer than usual to clot. A number lower than that range means blood clots more quickly than normal.
What is clotting time and bleeding time?The normal bleeding time is between 2-7 minutes. The normal clotting time in a person is between 8-15 minutes. By understanding the time taken for blood to clot, it can be determined if the person has haemophilia or von Willibrand's disease.
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