Testing if Sharks Can Smell a Drop of Blood

What is likely happening is that the sharks can smell the blood but it’s just not in a quantity that is interesting to them especially since they don’t love human blood that much (btw, I spoke with a marine biologist and mammal blood is all the same from a chemical marker stand point so cow blood is a suitable substitute for human blood). If I did the experiment again, I would want to test human blood vs. fish blood.