D-Dimer details

D-dimer is a protein fragment released into the blood when a blood clot is being broken down by your body's natural clot-dissolving process. It's used mainly to help rule out the presence of a blood clot, such as deep vein thrombosis (DVT) in the legs or a pulmonary embolism (a clot in the lungs) — a normal D-dimer, combined with a low clinical suspicion, makes a clot unlikely enough that further imaging can often be avoided. However, D-dimer is a nonspecific marker, meaning many other things can raise it too (recent surgery, pregnancy, infection, cancer, or simply older age), so an elevated result doesn't confirm a clot — it typically leads to imaging, like an ultrasound or CT scan, to look for one directly.