| Subject | Contents |
| Definition | This is an inherited disorder that causes prolonged clotting (coagulation) of blood in a test tube without a clinical bleeding tendency, and results from a deficiency of the plasma protein factor XII. |
| Alternative Names | |
| Causes, incidence, and risk factors | Factor XII deficiency is a hereditary disorder that is usually found when clotting tests are done for routine screening. It is not associated with abnormal bleeding , and is a rare disorder. |
| Symptoms | There are usually no symptoms. |
| Signs and tests | Prolonged partial thromboplastin time Abnormal Factor XII assay |
| Treatment | Treatment is generally unnecessary. |
| Support Groups | |
| Expectations (prognosis) | The outcome is expected to be good, even without treatment. |
| Complications | There are usually no complications. |
| Calling your health care provider | This condition is usually discovered by the health care provider when prolonged clotting is noticed in the process of running other laboratory tests. |
| Prevention | This is an inherited disorder. There is no known way to prevent it. |
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