Could 3 small bruises cause an elevated d-dimer? also, online info says vitamin c supplementation can affect ppt results. would they be high or low?

Bruises: don't cause elevations of d-Dimer. Typically no significant clots are actually formed in bruises....there is extravasation/leakage of blood into surrounding tissues with no clot. d-Dimer is released with clots begin to normally dissolve. I don't believe the evidence that coincident vitamin C intake causes an increase in d-Dimer is very convincing and would not worry about vitamin C interfering.

Labs: I'd be surprised if the d-dimer was up because of bruises, and would not discount a high value as part of the big picture just because you're been bruised. You know that many healthies have "elevated" this-or-that. People on megadose vitamin C may have extra oxalate in the blood that some folks suggest could bind the calcium reagent; this isn't something we actually worry about.