Negative d dimer day before calf pain started d/t possible dvt in other leg could the d dimer still be right even if day before sx. please help!

Unlikely to have DVT: Many causes of leg pain. Be examined and perhaps have duplex ultrasound depending on physical findings.

D dimer: D-dimer is a non specific test and can be positive for many reasons besides DVT. If you are having calf pain then you should have a venous duplex ultrasound which is the gold standard for diagnosing DVT between the groin and the lower calf.