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Also known as: '''''coagulation profile — clotting profile — clotting tests — tests of haemostasis

Also known as: '''''coagulation profile — clotting profile — clotting tests — tests of haemostasis

[[Image:Coagulation Cascade.jpg|thumb|right|350px|Coagulation cascade. Source: Wikimedia Commons; Author: Joe D (2007)]]

[[Image:Coagulation Cascade.jpg|thumb|right|350px|Coagulation cascade. Source: Wikimedia Commons; Author: Joe D (2007)]]

A prolonged PT may reflect a factor deficiency or the presence of a circulating inhibitor of coagulation. Repeating the test using a mix of test plasma and "normal" plasma can help differentiate these possibilities: PT returns to normal limits when normal plasma is added to factor-deficient plasma, but no change is seen when this is added to plasma containing inibitors³. PT is more sensitive than APTT for factor deficiencies.  

A prolonged PT may reflect a factor deficiency or the presence of a circulating inhibitor of coagulation. Repeating the test using a mix of test plasma and "normal" plasma can help differentiate these possibilities: PT returns to normal limits when normal plasma is added to factor-deficient plasma, but no change is seen when this is added to plasma containing inibitors³. PT is more sensitive than APTT for factor deficiencies.  

PT is affected by abnormalities or deficiencies in coagulation factors I, II, VII or X, for example in DIC, liver disease, or poisoning with vitamin K antagonists. Inherited defects are possible. PT is also prolonged by the presence of circulating anticoagulants. Inhibitors are often directed at factor X or thrombin and include fibrin degradation products and heparin³.

PT is affected by abnormalities or deficiencies in coagulation factors I, II, VII or X, for example in DIC, liver disease, endotoxaemia or poisoning with vitamin K antagonists. Inherited defects are possible. PT is also prolonged by the presence of circulating anticoagulants. Inhibitors are often directed at factor X or thrombin and include fibrin degradation products and heparin³. As factor VII has the shortest half-life of all the coagulation factors, if a patient is suffering a coagulation factor deficiency a prolonged PT is seen before a prolonged PTT as this factor is depleted most rapidly.

===Tests for Individual Clotting Factors===

===Tests for Individual Clotting Factors===

{{Learning

{{Learning

|literature search = [http://www.cabdirect.org/search.html?rowId=1&options1=AND&q1=%22Coagulation%22&occuring1=title&rowId=2&options2=AND&q2=tes*&occuring2=title&rowId=3&options3=AND&q3=&occuring3=freetext&x=65&y=9&publishedstart=yyyy&publishedend=yyyy&calendarInput=yyyy-mm-dd&la=any&it=any&show=all Coagulation Tests publications]

|literature search = [http://www.cabdirect.org/search.html?rowId=1&options1=AND&q1=%22Coagulation%22&occuring1=title&rowId=2&options2=AND&q2=tes*&occuring2=title&rowId=3&options3=AND&q3=&occuring3=freetext&x=65&y=9&publishedstart=yyyy&publishedend=yyyy&calendarInput=yyyy-mm-dd&la=any&it=any&show=all Coagulation Tests publications]

}}

}}

#[http://ahdc.vet.cornell.edu/clinpath/modules/coags/pivka.htm Cornell University Clinical Pathology Modules: Tests of Haemostasis - PIVKA]

#[http://ahdc.vet.cornell.edu/clinpath/modules/coags/pivka.htm Cornell University Clinical Pathology Modules: Tests of Haemostasis - PIVKA]

#Howard, M R and (2008) '''Haematology: an illustrated colour text''', ''Elsevier Health Sciences''.

#Howard, M R and (2008) '''Haematology: an illustrated colour text''', ''Elsevier Health Sciences''.

[[Category:Blood Samples and Coagulation Tests]]

[[Category:Blood Samples and Coagulation Tests]]

[[Category:Clinical Pathology]]

[[Category:Clinical Pathology]]

[[Category: To Do - Siobhan Brade]]

[[Category:Expert Review]]