Can two d dimers be wrong both negative convinced i have clot on lung?

See below: You have asked several questions about this recently. You said you had a Wells Score of 1.5 Be sure you are using the updated WELLS SCORE for PE(2-level). A wells score of less than 4.5= unlikely to be PE over 4.5= likely A negative D-Dimer with a "unlikely to be PE" score means you probably don't have a PE. BUT, YOU can't do your own wells score, because it requires physician input!!

Anything is possible: But as has been mentioned to you several times previously this test is quite specific, as in it is quite reliable about ruling out a process like a pulmonary embolus(lung blood clot) when negative. There are factors that can affect it's specificity, which have also been described to you in previous answers. It's still not clear from your questions why you are so sure this issue is clot related.

Depends: Interpreting the test result depends largely on the degree of suspicion prior to the test that you actually have PE. This is from pretest symptoms & physical exam findings: see the "Wells PE Criteria". If low prior suspicion (say 10%), a negative results means PE ~2%. If higher suspicion (say 50%), negative result PE ~ 14%, and may be reason for further testing, like spiral CT scanning.

Unlikely: D-dimer is very sensitive for blood clots. If neg, very unlikely to have blood clot, if positive/high, may have blood clot or something else such as infection.

Yes: Your d dimer can be elevated just from brushing your teeth too hard.

Negative predictive: A negative result for D-dimer has a strong predictive value for excluding a thrombus, it is accurate to about 98%. Two negative D- dimer results virtually ensure that you do not have blood clot in the veins or lungs.