Question

Is there a blood test that can check for the presence of blood clots?

Answer 1

Yes, D-dimer

Explanation:

For the most part, the body will break down blood clots on its own, via fibrinolysis. Of course, this is a slow process, and in that time period, the clot may move and occlude a blood vessel somewhere - causing an acute emergency (stroke, pulmonary embolism etc.)

When a clot is being broken down by the body, it releases protein fragments known as fibrin degradation product (FDP). The presence of which is what a D-dimer assay tests for.

However, it does not provide definitive results, so if there is still a clinical suspicion for a venous-thromboembolism (VTE) despite a negative reading, then radiological studies will likely still need to be performed.

Some conditions that I frequently see causing false positives in-particular are malignancy (cancer), and pregnancy.