The color of blood

My 14 year old son and I were driving in the car with his 15 year old cousin. Jake was checking his blood on his palm but usually checks on his finger. His cousin glanced over as he was finishing and noticed the orange marker that was smeared on his finger (which is why he used his palm) and gasped. "Oh my god, do all diabetics have orange blood?"  My son and I calmly looked at each other, and replied, "the color is different depending on how much sugar is in his blood at the time!" My poor, naive nephew believed every word! We now joke regularly about what color his blood is today!