I'm on coumadin (warfarin) 7.5 daily. recently have lung pain. had pes in the past. small ones. is a d dimer accurate on coumadin (warfarin)?

No: D-dimer can be effected by Coumadin (warfarin) and increased inr.

Dd and warfarin: Conventional intensity warfarin will typically decrease the sensitivity of Dd testing, so if Dd s are used to predict recurrence of venous thrombosis, it is best to do so off warfarin. Oftentimes the "size" of lung clots are related to their severity, but not always i.e. in patients with cardiopulmonary disease, even "small" clots can be fatal.