Diagnostics·Diagnostics
D-dimer test
Informed by recognized medical guidance
Overview
A D-dimer test is a blood test that helps doctors check for blood clotting problems. It measures a substance called D-dimer, which is released when a blood clot breaks down. A normal result makes it very unlikely that you have a dangerous blood clot, but a high result can happen for many reasons and does not mean you definitely have a clot.
Key facts
- The test is used to help rule out deep vein thrombosis (DVT) and pulmonary embolism (PE).
- A negative result is very reliable for ruling out clots in people with low risk.
- A positive result does not confirm a clot; further tests like an ultrasound or CT scan are usually needed.
D-dimer tests are common in hospitals and clinics, especially in emergency departments when someone has symptoms that could be from a blood clot.
It is used for people of any age who have symptoms that could be from a blood clot. Doctors may order it for people with leg pain or swelling, or sudden shortness of breath.