That Horseshoe Crab must really Love you …
it gave it’s blood to saved your life.

Did you know that a horseshoe crab has probably saved your life?

It’s true…..

Horsehoe crab blood used to test drugs and implants

Horseshoe crab blood is used to test drugs and implants for endotoxins. Endotoxins are byproducts of bacteria that remain even after sterilization. Endotoxins, if injected into the blood stream can cause fever, coma and possibly death.

A horseshoe crab has blue blood which is copper based instead of iron based like our blood ( that’s why it’s blue instead of red). This blood has another unique quality, horseshoe crabs blood will gel when it comes in contact with bacteria or endotoxins.

This action is part of the horseshoe crabs primitive immune system. If a horseshoe crab sustains an injury such as a cut, when bacteria tries to enter it’s body, it’s blood jells which creates a barrier against the bacteria.

Biomedical companies have found a way to extract the compound that makes their blood jell from amebocytes (the only blood cell present ) in the horseshoe crab’s hemolymph.

This preparation is called Limulus Amebocyte Lysate (LAL). LAL is used to detect endotoxins associated with gram-negative bacteria. These pathogenic bacteria can illicit a pyrogenic response if introduced into the human blood stream, which involves fever, coma or even death.

LAL is used by pharmaceutical and medical industries to ensure that their products (e.g., intravenous drugs, vaccines, and implantable medical and dental devices) have no bacterial contamination. They take a sample and introduce the LAL. If it jells they know that batch is contaminated and must be disposed of.

This is currently the most effective way to test for gram negative endotoxins.

Horseshoe Crab blood saves our lives again and again

So if you have ever had a tetanus shot, a flu shot or any kind of shot a horseshoe crab has made it possible without you getting sick or possibly dying. So when you get your next shot, thank a horseshoe crab that helped to make sure that it was safe.

The Horseshoe Crab Controversy

Biomedical Companies need a large supply of horseshoe crabs in order to extract their blood. Luckily they don’t have to kill the horseshoe crabs What they do is they harvest the horseshoe crabs and then only extract about 1/3 of it’s blood and then they release the horseshoe crabs back into the wild.

It is estimated that it takes about 30 days for the horseshoe crab to replace the blood that was extracted. The biomedical companies report that the process of bleeding causes a 10% mortality rate, but that rate could be much higher.

The Problem lies with the fact that fishermen also need horseshoe crabs for bait when they fish for conch and their use of large numbers of horseshoe crabs started to deplete the horseshoe crab populations. The legislators have put a limit on how many horseshoe crabs that can be taken and now it seems that the horseshoe crab population is on the rebound.


The fishing industry is now pushing for a lift on the limit that they can take for bait .  We’ll just have to see where this all ends, but it is for certain that it is everybodies interest that there be a healthy horseshoe crab population in the wild.

David Hodgson (32 Posts)