It may be ordered when someone has symptoms of pulmonary embolism such as:
Sudden shortness of breath, labored breathing
Coughing, hemoptysis (blood present in sputum)
Lung-related chest pain
Rapid heart rate
D-dimer is especially useful when a health practitioner thinks that something other than deep vein thrombosis or pulmonary embolism is causing the symptoms. It is a quick, non-invasive way to help rule out abnormal or excess clotting. However, it should not be used when the probability of pulmonary emobism is high based on clinical assessment.
When a person has symptoms of disseminated intravascular coagulation (DIC), such as bleeding gums, nausea, vomiting, severe muscle and abdominal pain, seizures, and decreased urine output, a D-dimer test may be ordered, along with a PT, PTT, fibrinogen, and platelet count, to help diagnose the condition. D-dimer may also be ordered at intervals when someone is undergoing treatment for DIC to help monitor its progress.
A normal or negative D-dimer result (D-dimer level is below a predetermined threshold) means that it is most likely that the person tested does not have an acute condition or disease causing abnormal clot formation and breakdown. Most health practitioners agree that a negative D-dimer is most valid and useful when the test is done for people who are considered to be at low to moderate risk for thrombosis. The test is used to help rule out clotting as the cause of symptoms.
A positive D-dimer result may indicate the presence of an abnormally high level of fibrin degradation products. It indicates that there may be significant blood clot (thrombus) formation and breakdown in the body, but it does not tell the location or cause. For example, it may be due to a venous thromboembolism (VTE) or disseminated intravascular coagulation (DIC). Typically, the D-dimer level is very elevated in DIC.
However, an elevated D-dimer does not always indicate the presence of a clot because a number of other factors can cause an increased level. Elevated levels may be seen in conditions in which fibrin is formed and then broken down, such as recent surgery, trauma, infection, heart attack, and some cancers or conditions in which fibrin is not cleared normally, such as liver disease. Therefore, D-dimer is typically not used to rule out VTE in hospitalized patients (inpatient setting).
Fibrin is also formed and broken down during pregnancy, so that may result in an elevated D-dimer level. However, if DIC is suspected in a woman who is pregnant or is in the immediate postpartum period, then the D-dimer test may be used, along with a PT, PTT, fibrinogen, and platelet count to help diagnose her condition. If the woman has DIC, her D-dimer level will be very elevated.
D-dimer is recommended as an adjunct test. Since D-dimer is a sensitive test but has a poor specificity, it should only be used to rule out deep vein thrombosis (DVT), not to confirm a diagnosis. It should not be used for pulmonary embolism when the clinical probability of that condition is high. Both increased and normal D-dimer levels may require follow-up and can lead to further testing. People with positive D-dimer tests and those with moderate to high risk for DVT require further study with diagnostic imaging.
When used to monitor DIC treatment, decreasing levels indicate that treatment is effective while increasing levels may indicate that treatment is not working.
There are several different methods of testing for D-dimer. The currently available D-dimer tests that yield quantitative results are typically done in a hospital lab. Since different tests are used in different units, the results of one cannot be extrapolated to another.
This article was last reviewed on December 17, 2014. | This article was last modified on February 23, 2015.
The review date indicates when the article was last reviewed from beginning to end to ensure that it reflects the most current science. A review may not require any modifications to the article, so the two dates may not always agree.
The modified date indicates that one or more changes were made to the article. Such changes may or may not result from a full review of the article, so the two dates may not always agree.