What is a d dimer test result of 0.77 mean?

It is a little bit higher than normal (<0,5) but it is not shocking.

D-dimers are the products that result if a blood clot disolves in your blood. If you have high levels, there is a good possibility that you have DIC: Disseminated intravascular coagulation. This is a serious desease.

Maybe you want to go to a docter and check out the course of your D-dimer. You don't want the level to get high.