Clotting time - Wikipedia Clotting time This article needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. ( February 2017 ) Clotting time is the time required for a sample of blood to coagulate in vitro under standard conditions. There are various methods for determining the clotting time, the most common being the capillary tube method. It is affected by calcium ion levels and many diseases. Normal value of clotting time is 8 to 15 minutes. For the measurement of clotting time by test tube method, blood is placed in a glass test tube and kept at 37 ° C. The required time is measured for the blood to clot. There are several other methods, including testing for those on blood thinners, such as heparin or warfarin. Activated partial thromboplastin time ( aPTT ) is used for heparin studies and the normal range is 20 -- 36 seconds, depending upon which type of activator is used in the study. Prothrombin time ( PT ) is used for warfarin studies and the normal values differ for men and women. PT time for adult males ' normal range is 9.6 -- 11.8 seconds, while adult females ' normal range is 9.5 -- 11.3 seconds. Internationalized normalized ratio ( INR ) is also a warfarin study, with normal ranges of 2 -- 3 for standard warfarin and 3 -- 4.5 for high - dose warfarin. References Jump up ^ Dg, Dayyal ( 2016 ). `` Bleeding Time ( BT ) and Clotting Time ( CT ) ''. BioScience. ISSN 2521 - 5760. Retrieved 2017 - 10 - 26. ^ Jump up to : Silvestri, Linda ( 2014 ). Saunders comprehensive review for the NCLEX - RN examination. St. Louis, MO : Elsevier. pp. 116 -- 117. ISBN 978 - 1 - 4557 - 2755 - 1. This immunology article is a stub. You can help Wikipedia by expanding it. Retrieved from `` https://en.wikipedia.org/w/index.php?title=Clotting_time&oldid=838662632 '' Categories : Blood Immunology stubs Hidden categories : Articles needing additional references from February 2017 All articles needing additional references All stub articles Talk About Wikipedia Edit links This page was last edited on 28 April 2018, at 13 : 31. About Wikipedia

Question: what is the normal clotting time for blood
Answer: 8 to 15 minutes