Originally Posted by
GommeInc
Mentor and I have come with an explaination. Ostinato, you are very wrong with this idea of air in the needle. It wouldn't make the blood test sterile and air in the needle would contaminate the sample, making it pointless. Besides, air in the needle will kill, when a doctor pushes the needle into you, they may accidently push on the plunger bit, which would release a small amount of air, which will be dangerous... I believe it comes down to pressure, so air cannot be in the needle and if it is, it must be released somewhere.
So this means blood in veins IS a darker shade of red, not blue. Because as Mentor says, you seem to lack the idea of common sense that blood is made of RED blood cells, white blood cells etc, no blue is in there. RED cannot change colour to blue, unless you mix it with something, which you can't because you cannot make the colour blue without blue I believe.