PT/INR done on wrong patient... what's in store?

Dr. ordered a PT/INR for a pt. but nurse accidentally did on the incorrect pt. Luckily that pt. was also on coumadin and in the process of having their levels checked earlier in the week (but was recently found to no longer require) but no less -- wrong pt. How much trouble is this nurse in for would you say? Thanks...
I don't think that it's such a serious offense. Labs can be drawn the next day, this time for the right patient. It's not as if they labeled the samples wrong. I would still suggest talking to the nurse and see what happened to prevent a serious incident from happening.

So did the right patient end up getting their INR checked?