donating blood after gastric bypass

Question
I donated blood this past Tuesday and early Thursday morning I woke up extremely dizzy and nausia.  So much that I could not go to work that day.
I am trying to figure out if donating blood earlier could of caused this side effect for me or if perhaps I woke up ill.  I had the bypass two years ago and have been light headed a few times, but never to this extreme.

Thank you for your advice.
PS:  Red Cross had no information on this concerning bypass, but did say you could have some dizziness.

Answer
Bonnie,

In 5 years I never had this question - then twice this week...

Usually, before you donate blood, they do a little screen for anemia.  However, this screen only really tells them if your circulating blood is OK - not whether your storage is good (which at 2 years post op it may not be).  This screen also doesn't tell you how your B12 or folate stores are. You need good iron stores to make new cells after you donate blood - and healthy levels of some of these other nutrients as well.  

While I have not seen anything formal suggesting that gastric bypass patients should not give blood, I am beginning to think it may not be a good idea.  

I think I am going to also pose this questions to some other experts to hear their opinions and experience.

In Health,

Dr. Jacques

1. Prev:I hate my body!
2. Next:VERTICAL SLEEVE GASTRECTOMY