How high would a d dimer be to make you think clot mine was slightly elevated first 310 should be 230 second time 263 should be 243?

Just a test. D-dimer is one of the parameter used for diagnosis. It can also be elevated in other conditions. So your physician must look at the history to include risk factors/physical exam/US/CT SCAN to make a diagnosis. but in case you do smoke please stop smoking.