Platform
Company
Coagulation
Review status
Currently under review
Pending specialist review and validation.
Factor XIII is a blood clotting protein that stabilizes a forming clot so it can withstand normal blood flow and protect against rebleeding. After fibrin strands are built, Factor XIII helps cross link them, which strengthens the clot and supports tissue repair. A deficiency can leave clots fragile and more likely to break down too soon.
This test most often measures Factor XIII activity in platelet poor plasma. It may be paired with antigen assays or inhibitor studies to determine whether a low result is due to reduced protein amount, reduced function, or an antibody that blocks its action.
Clinicians order Factor XIII testing when there is unexplained bleeding, normal routine clotting tests, poor wound healing, bleeding after childbirth or surgery, or a history suggesting an inherited clotting disorder. It can also be used to evaluate recurrent pregnancy loss, where fragile clots at the implantation site may play a role.
Results help distinguish inherited Factor XIII deficiency from acquired causes related to autoimmune inhibitors, severe liver disease, consumptive coagulopathy, or major inflammation. Testing can also assist in monitoring replacement therapy and ensuring adequate clot stability before procedures.
If your result is within the expected range for the laboratory, it generally suggests that your clots can be properly stabilized. A low result indicates a deficiency that may be inherited or acquired. Your clinician may confirm the finding with repeat testing, perform an antigen level, or look for an inhibitor. Genetic testing may be considered when an inherited condition is suspected.
When deficiency is confirmed, treatment and follow up depend on the cause and your clinical situation. Options may include replacement therapy, addressing an autoimmune process, or treating an underlying condition such as liver disease. If you are pregnant, planning a pregnancy, or facing surgery, discuss preventive strategies with your care team so that a personalized plan is in place.
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.
The test requires proper filling of the blue top citrate tube, gentle mixing, and prompt processing. Underfilling, clotting in the tube, or delays in centrifugation and freezing can artifactually lower activity.
Transfusion of plasma or treatment with Factor XIII concentrate can increase measured activity for a period of time, potentially masking an underlying deficiency. Tell your clinician about any recent products you received.
Severe liver dysfunction, disseminated intravascular coagulation, and major inflammatory states can reduce Factor XIII levels or function, leading to acquired deficiency that may improve as the underlying condition is treated.
Autoimmune inhibitors can block Factor XIII activity and cause bleeding despite normal routine clotting tests. Some medications and biologics may contribute to inhibitor formation; provide a full medication list.
Physiologic changes in pregnancy and with estrogen therapy can influence clotting proteins. Testing and interpretation may be tailored in these settings, particularly if there is a history of pregnancy loss or bleeding.
Inherited Factor XIII deficiency presents from infancy to adulthood with variable severity. Family history, genetic testing, and correlation with symptoms help clarify lifelong risk and guide preventive care.
References