Gram Stains does not recognize endotoxin

Endotoxins are molecules from the cell walls of certain bacteria,including E. coli. Large amounts of them are released when

bacterial cells die, and they can make us sick if they enter the blood stream. Many of the medicines and medical devices we

rely on can become contaminated, so we have to test them before they touch our blood.We do have tests called Gram stains that

detect bacteria, but they can't recognize endotoxins which can be there even when bacteria aren't present.