Is a d-dimer enough to rule out a dvt or pulmonary embolism. suffering from chest pain,shortness of bteath, n burning n swelling in legs n back?

Yes.: Yes, D-diner has a high negative predictive value. That means that if the test is negative, it strongly predicts the ABSENCE of DVT. Iss positive predictive value is lower; that is, D-dimmer may be positive but the patient not have DVT.

Yes: If a D dimer is negative, you are unlikely to have a DVT or Pulmonary Embolism. If it is positive, it does not mean you do have a DVT or Pulmonary Embolism as other chronic conditions can cause an elevated D dimer and further tests such as doppler ultrasound of the lower extremity or Chest CT with Pulmonary Embolism Protocol has to be done for further evaluation.

Not 100%: negative ddimer makes it very unlikely but a positive ddimer requires further testing

Yes and no: d-dimer is quite a good test to rule out DVT and PE in patients with low and moderate risks. so for the most part, yes, if the d-dimer is negative, the probability of one having DVT and PE are quite low. The caveat, however, is in "high risk" patients, according to well's algorithm, a more definitive test (like a CT) is needed.

In some settings.: In the outpatient setting, where you have not had recent surgery or other reasons to put you into a "high risk" category, a negative d-dimer is enough to eliminate DVT/pulmonary embolism from the differential diagnosis. On the other hand, a positive d-dimer is not specific for PE, it only tells you to do further testing such as doppler ultrasound, CTPAgram or V/Q scan.