References American Heart Association [Internet]. Dallas: American Heart Association Inc. What is Excessive Blood Clotting Hypercoagulation? Atlanta: U. Coagulation Factor Assay; p. Bleeding Disorders [cited Oct 30]; [about 3 screens]. Washington D. Overview of Blood Clotting Disorders [cited Oct 30]; [about 2 screens]. Bethesda MD : U. New York: National Hemophilia Foundation; c Other Factor Deficiencies [cited Oct 30]; [about 3 screens]. What is a Bleeding Disorder [cited Oct 30]; [about 2 screens].
Coagulation Disorders [cited Oct 30]; [about 3 screens]. University of Florida; c Factor X deficiency: Overview [updated Oct 30; cited Oct 30]; [about 2 screens].
The final step of this cascade of chemical reactions is to convert factor I also called fibrinogen - a soluble protein into thin strands of a solid protein called fibrin. The strands of fibrin form a meshwork and trap blood cells which form into a solid clot. If a blood clot forms within a healthy blood vessel it can cause serious problems.
So, there are also chemicals in the blood that prevent clots from forming and chemicals that 'dissolve' clots. There is balance between forming clots and preventing clots. Normally, unless a blood vessel is damaged or cut, the 'balance' tips in favour of preventing clots forming within blood vessels.
Blood is made up of liquid plasma and various different types of cells. An average-sized man h There are various conditions where you tend to bleed excessively if you damage or cut a blood vessel - for example:. Sometimes a blood clot forms within a blood vessel that has not been injured or cut - for example:. There are a number of different tests. The ones chosen depend on the circumstances and the suspected problem.
They include the following:. A full blood count is a routine blood test that can count the number of red cells, white cells and platelets per millilitre of blood. It will detect a low level of platelets. In this test, a tiny cut is made in your earlobe or forearm and the time taken for the bleeding to stop is measured. It is normally minutes. A blood sample is taken into a bottle that contains a chemical which prevents the blood from clotting.
It is then analysed in the laboratory. Other inherited factor deficiencies are not associated with the X chromosome and are much rarer than Haemophilia A and B. The severity of symptoms experienced by a patient with an inherited factor deficiency depends on which factor is involved, how much of it is available and whether or not it is functioning normally.
Symptoms may vary from episode to episode, from a minor prolonged nosebleed to severe recurrent bleeding into areas such as the joints. While a patient may not have trouble with a small puncture or cut, a surgery, dental procedure, or trauma could put them into a bleeding crisis. Those with severe factor deficiencies may have their first bleeding episode very early, for example a male infant with a factor VIII deficiency may bleed excessively after circumcision.
On the other hand, patients with mild bleeding disorders may experience few symptoms and may discover their deficiency as an adult - after a surgical procedure or trauma, or during a screening that includes a PT or APTT test. Acquired deficiencies may be due to chronic disease, such as liver disease or cancer; to an acute condition such as disseminated intravascular coagulation DIC , which uses up clotting factors at a rapid rate ; or to a deficiency in vitamin K the production of factors II, VII, IX, and X requires vitamin K.
They may also be due to anticoagulant medications such as warfarin. Acquired conditions may involve multiple factor deficiencies that must be identified and addressed. Typically, a blood sample is drawn from a vein in the arm. As an alternative, particularly in paediatric care, the blood sample is drawn from the fingertip. Factor testing is usually done as a follow-up to abnormal prothrombin time PT and activated partial thromboplastin time APTT testing or if you experience abnormal bleeding.
If one or both are abnormal, the suspected coagulation factor deficiencies they suggest may then be tested for individually. Additional testing may be done, especially when multiple deficiencies are involved, to look for underlying health problems that may be causing an acquired deficiency.
Sometimes factor testing may be done on a patient with a known deficiency to monitor the factor deficiency and to evaluate the effectiveness of treatment. If the patient has an acquired condition, factors may sometimes be monitored to see if they have worsened with a progressive disease or have got better because of treatment of the underlying condition. Patients may be tested when they have a suspected acquired condition that is causing bleeding, such as DIC, pregnancy-related eclampsia, liver disease or a vitamin K deficiency.
Factor testing may be done if an inherited factor deficiency is suspected, especially when bleeding episodes begin early in life or when a close relative has an inherited factor deficiency. Both functional factor testing activity and quantity testing antigen may be done to evaluate the severity of the deficiency.
Other reasons for abnormal results include hemophilia , liver disease, and malabsorption. Read more: Prothrombin time test ». Results are given in the number of seconds it takes the blood to clot. Sometimes the PT test uses a calculation called the international normalized ratio INR to compare results of different laboratories.
Your doctor will usually order the PT test along with another clotting test called an activated partial thromboplastin time aPTT. Platelets are cells in the blood that help your blood clot. Other causes of a low platelet count are celiac disease , vitamin K deficiency, and leukemia.
Learn more: Low platelet count thrombocytopenia ». Anemia , primary thrombocythemia , or chronic myelogenous leukemia CML may cause an abnormally high number of platelets. Thrombin time measures how well fibrinogen is working. Abnormal results may be due to inherited fibrinogen disorders, liver disease, some cancers, and medications that affect clotting.
This test analyzes how quickly small blood vessels in your skin close up and stop bleeding. A blood pressure cuff will be placed on your upper arm and inflated. Your healthcare provider will make a couple of tiny cuts on your lower arm.
Bleeding usually lasts between one to nine minutes. The test is considered safe and carries few side effects or risks. Coagulation tests are conducted the same way as most blood tests. You may need to discontinue taking certain medications prior to the test. No other preparation is necessary. Your healthcare provider will sterilize a spot on the back of your hand or inside your elbow.
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