Platform
Company
Coagulation
Review status
Currently under review
Pending specialist review and validation.
This test measures the activity of Factor X, a vitamin K dependent clotting protein made by your liver. Factor X helps drive a key step in the clotting cascade that leads to the formation of a stable blood clot. The assay is performed on citrated plasma using a one stage method with a standardized dilution to keep the result within the working range of the analyzer.
It is used alongside other clotting tests to understand how well your clotting system is functioning and to look for conditions that affect Factor X production or function.
Clinicians order this test when you have unexplained bruising or bleeding, a prolonged prothrombin time, before procedures, or when there is concern about liver function or vitamin K status. It can also be used when a rare inherited Factor X deficiency is suspected or to assess the effect of certain therapies.
Results help guide decisions about treatment, such as giving vitamin K, adjusting anticoagulant medicines, or considering factor replacement. The result can also point to underlying causes like liver disease or an inhibitor that interferes with clotting.
If your Factor X activity is lower than expected, your care team will consider inherited deficiency, reduced production from liver or vitamin K problems, or the impact of medicines. Follow up may include mixing studies, other factor assays, checks of prothrombin time, and evaluation of liver and nutritional status to clarify the cause.
If your activity is higher than expected, it is usually not harmful by itself and may reflect recent factor replacement or changes during inflammation or pregnancy. Your clinician will interpret the result in context with your symptoms and other tests. If the number does not match your clinical picture, the test may be repeated, sample handling reviewed, or a different method used to rule out interference.
Reference intervals vary by laboratory, analyzer, methodology, population, and units. The ranges shown here are for education only. Always interpret your results against the reference interval printed on your own lab report.
Warfarin lowers vitamin K dependent factors, including Factor X, which can reduce measured activity. Some direct oral anticoagulants and heparin may interfere with one stage clotting assays, leading to falsely low or variable results.
Poor intake, malabsorption, prolonged antibiotic use, or bile duct problems can reduce vitamin K availability and lower Factor X production. Your clinician may review diet, supplements, and gut health when interpreting results.
Factor X is made in the liver. Liver diseases, including acute injury or chronic conditions, can decrease production and lower activity. Other liver tests are often checked to provide context.
Citrate tubes must be filled to the line and mixed gently. Underfilling, clotting in the tube, delayed processing, or very high hematocrit can artifactually alter results. Proper collection reduces these pre analytic errors.
Specific inhibitors to Factor X are rare but can lower measured activity. Lupus anticoagulant or other inhibitors may prolong clot based assays and confound interpretation. Mixing studies can help distinguish these.
Physiologic changes in pregnancy and acute phase responses can increase some clotting factors. This may raise activity measurements without indicating a disorder.
References