CT scan of lungs
The beginning of all good testing is having the doctor take a good history and do a good physical exam. If the results are strongly suggestive of someone having a blood clot
in the lungs (pulmonary embolism
-pe), then a blood test called a d-dimer might be ordered.
If that is low, you don't have a clot. If high, the gold standard of testing for a pe is a spiral cat scan of the lungs with infusion.