20 Things You Somehow Missed In X-Men
9. Wolverine's Blood Is Tested For Metal
After Wolverine and Rogue are rescued near the start of the movie, they're brought to the X-Mansion where we see Jean Grey (Famke Janssen) attempting to take Wolverine's blood, before he freaks out and interrupts her.
Fittingly, the tube which Jean is holding to collect the blood is coloured dark blue, which is commonly used in medicine when blood is being tested for metal content.
Given Wolverine's physical characteristics, that makes all the sense in the world, yet it's a detail of scientific accuracy so insignificant that nobody outside of the medical industry would likely ever know about it. Impressive.