Had two negative d dimers chance of pulmonary embolism?

It depends to your: symptoms and other lab. findings. Sometimes spiral ct scan and pulmonary angiogram is necessary to rule out a pulmonary embolism.

Very low possibility: It is a very good test to rule out PE but there is always a chance to miss PE with test; but low likelihood to have PE if test is neg. One study showed that the sensitivity of the D-dimer ELISA for acute PE was 96.4% negative predictive value was 99.6% --this all means is a very good test.