Recently, Tanya Koenig <tanya@Radix.Net>, pointed out a very common science blunder that a lot of shows make, including non-SF shows:
I believe someone else mentioned this when it came out, but one of the recent episodes of Dark Angel (Blah Blah, Woof Woof?) had the classic blood type blunder–“AB- is the rarest blood type and we don’t have any on hand.” While technically true, it ignores the fact that AB is the universal recipient and only the Rh Factor needs to be considered.
Now if he’d been type O….
I even remember this blunder on the A-Team. Actually, what makes AB- (“Aye-Bee-Negative”) really rare is the Rh negative. The vast majority of people are Rh positive; in fact, it’s harder to find people who are Rh negative (approximately 16% of the population). So all you need is O-, which is easier to find than AB-. In a life-threatening pinch, you could use O+ on an AB- recipient, but doctors prefer bang on matching.
Although Karen Davis pointed out:
Just thought I’d point out — you say all you need is O- for an AB- person. Actually, AB is the universal recipient, therefore all you need is O-, or A-, or B-, or AB-. Some 16% of the population will do. B- is actually the harder to do (though again, tv shows often ignore the fact that O- will do; I’m remembering a Rat Patrol episode in particular). O- would be harder, though there are more O- people around.
The Red Cross has a useful FAQ on blood typing.