This is a common but outdated belief of many doctors. If it is not the same type ( and according to many Experts there are hundreds each with own subtypes ) then Yes they are playing Russian roulette with you.
They are deliberately giving you the wrong type. Asking that question on a bloodless medicine site you must be aware of all the dangers of transfusions-even of the'right type'
Watch Primum Non Nocere-1st do no harm at asiageographics ( $9 to watch $19 to download )
What is more interesting is that your own blood once it leaves your body for more than 2 or 3 hours -"Is Not The Same" -chemical changes are already taking place -not to your benefit. -Sherrie R.N. director at Englewood
Over 50 years ago it was known by some that blood is as individualistic as fingerprints - you can't match that.
Watch both parts of a Caucus New Jersey show online at youtube http://www.youtube.com/user/pnutts27/videos - I had permission to upload it there.
You can also watch 2 videos at Englewood Hospital's website quickest way there is type www.bloodlessmed.com - video links are on right side.