What is a good means of determining if i have a blood clot?

LookAtIt, BloodStops: You did not specify where. Ideally clots form only at blood vessel breaks (no endothelium & the no-clot/clot seesaw flips). However, for clots inside blood vessels, angiography works best (narrowing or closure by clot visible by lack of dye/blood flow) or via ultrasound (much less detail/clarity) view of opening, blood motion on doppler or increase of flow speed (past a narrowing, i.e. The clot).

Depends on where: Venous blood clots in the arms and legs often produce swelling and a fullness like pain, and sometimes a discoloration however can be present without symptoms especially in their early stages. Other symptoms can be unexplained fever or shortness of breath. An good history and physical with an ultrasound if indicated will help. Do you have risk factors? This is an improtant discussion point.