BACK TOTOP Browse A-ZSearchBrowse A-ZABCDEFGHIJKLMNOPQRSTUVWXYZ0-9 E-mail FormEmail ResultsName:Email address:Recipients Name:Recipients address:Message: Print-FriendlyBookmarksbookmarks-menuProtein C blood testAutoprothrombin IIAProtein C is a normal substance in the body that prevents blood clotting. A blood test can be done to see how much of this protein you have in your blood. How the Test is Performed A blood sample is needed.Blood sampleVenipuncture is the collection of blood from a vein. It is most often done for laboratory testing.Read Article Now Book Mark Article How to Prepare for the Test Certain medicines can change blood test results.Tell your health care provider about all the medicines you take. Your provider will tell you if you need to stop taking any medicines before you have this test. This may include blood thinners. Do not stop or change your medicines without talking to your provider first. How the Test will Feel When the needle is inserted to draw blood, some people feel moderate pain. Others feel only a prick or stinging. Afterward, there may be some throbbing or slight bruising. This soon goes away. Why the Test is Performed You may need this test if you have an unexplained blood clot or a family history of blood clots. Protein C helps control blood clotting. A lack of this protein or a problem with the function of this protein may cause blood clots to form in veins.The test is also used to screen relatives of people who are known to have protein C deficiency. It may also be done to find the reason for repeated miscarriages.Protein C deficiencyCongenital protein C or S deficiency is a lack of proteins C or S in the fluid part of the blood. The proteins are natural substances that help prev...Read Article Now Book Mark Article Normal Results Normal values are 60% to 150% inhibition.Normal value ranges may vary slightly among different laboratories. Some labs use different measurements or may test different samples. Talk to your provider about the meaning of your specific test results. What Abnormal Results Mean A lack (deficiency) of protein C can lead to excess clotting. These clots tend to form in veins, not arteries.Protein C deficiency can be passed down through families (inherited). It can also develop with other conditions, such as:Chemotherapy use Disorder in which the proteins that control blood clotting become over active (disseminated intravascular coagulation) Disseminated intravascular coagulationDisseminated intravascular coagulation (DIC) is a serious disorder in which the proteins that control blood clotting become overactive.Read Article Now Book Mark Article Liver disease Long-term antibiotic use Warfarin (Coumadin) useA problem such as a sudden blood clot in the lung may reduce the protein C level.Sudden blood clot in the lungA pulmonary embolus is a blockage of an artery in the lungs. The most common cause of the blockage is a blood clot.Read Article Now Book Mark Article Protein C level rises with age, but this does not cause any health problems. Risks There is little risk involved with having your blood taken. Veins and arteries vary in size from one person to another, and from one side of the body to the other. Obtaining a blood sample from some people may be more difficult than from others.Other risks associated with having blood drawn are slight, but may include:Excessive bleeding Fainting or feeling lightheaded Multiple punctures to locate veins Hematoma (blood accumulating under the skin) Infection (a slight risk any time the skin is broken)Open ReferencesReferencesAnderson JA, Hogg KE, Weitz JI. Hypercoagulable states. In: Hoffman R, Benz EJ, Silberstein LE, et al, eds. Hematology: Basic Principles and Practice. 7th ed. Philadelphia, PA: Elsevier; 2018:chap 140.Chernecky CC, Berger BJ. Protein C (autoprothrombin IIA) - blood. In: Chernecky CC, Berger BJ, eds. Laboratory Tests and Diagnostic Procedures. 6th ed. St Louis, MO: Elsevier Saunders; 2013:927-928.AllVideoImagesTogA Closer Look High blood pressure(Alt. Medicine)High blood pressure(In-Depth)Diabetes - type 1(In-Depth)Diabetes - type 2(In-Depth)Diabetes(Alt. Medicine)Myocardial infarction(Alt. Medicine)Atherosclerosis(Alt. 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Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team. The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed medical professional should be consulted for diagnosis and treatment of any and all medical conditions. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. © 1997- © 1997- All rights reserved. A.D.A.M. content is best viewed in IE9 or above, Firefox and Google Chrome browser.Content is best viewed in IE9 or above, Firefox and Google Chrome browser.