D-dimer-test

D-dimer test

A D-dimer test measures a specific protein fragment that appears in the blood when the body breaks down a blood clot. It is useful because a low D-dimer result makes it unlikely that a person has a new, significant clot, so the test is often used to rule out conditions like deep vein thrombosis or pulmonary embolism in people with low clinical risk. A positive or high D-dimer does not prove there is a dangerous clot, because many things — including recent surgery, infection, inflammation, pregnancy, or cancer — can raise D-dimer levels. Because the test is sensitive but not specific, doctors usually interpret it together with a clinical risk assessment and may order imaging scans if the result and symptoms suggest a clot. The test is fast and widely available, which makes it valuable in emergency and urgent-care settings to help decide who needs further testing. Limitations include false positives in older adults and people with other medical conditions, so a high result often leads to follow-up tests rather than immediate treatment. Overall, the D-dimer test is a helpful screening tool that can reduce unnecessary scans but must be used carefully with other clinical information.