Blood Type?

This morning I will go up to the hospital because I need to list my blood type on a medical information form for Operation: Prayer SURGE. I did not think this would be difficult information to find. Shows what I know!
Last week I phoned the assorted MDs. I figured that after all the surgeries, the births of three babies, and the blood transfusions one of the assorted 'ologists would have my blood type on file. I thought wrong. Even the OB who delivered lovely Little Bit, performed several other surgeries on me, and eventually had to order transfusions following a nasty bit of post-op internal bleeding does not have a record of my blood type. (Um. Didn't she need that for the transfusion?!) I figured if all the doctors were not helpful, maybe the nursing agency that handles my IVIG would have it. Nope.
So I called in the big guns. I called my Mom. She had no idea. She was guessing in the AB arena. My Dad phoned later to say he had unearthed his blood type and it was not as previously believed, but was instead the O+ that my IVIG nurse and I were speculating to be my likely blood type. I'm going to try the hospital's medical records this morning. Theoretically, they should have that on file somewhere...
If not, then I have two remaining options: I can go pick up a lab slip for blood typing or I can just pick a blood type to write-in on the health forms for Great Commission Ministries to keep on file for the Poland trip. I'm hoping the hospital records will confirm the O Positive I strongly believe to be correct.