Does negative d diners rules out pulmonary embolism ?

It should: The answer really depends on the patient. D-dimers will be positive if your body is forming and then breaking down clot somewhere. This is usually positive in the setting of a DVT or pulmonary embolism. Like all tests, this one can be either falsely negative or falsely positive. If you remain concerned, talk to your doctor.

Usually: The d dimer test, if negative makes a clot very unlikely. A positive test thought is no guarantee or "lock" that you have one. The negative predicative value is high for the d dimer test.