August 23, 2021 — It’s one of the stranger, lesser-known aspects of U.S. health care — the striking, milky-blue blood of horseshoe crabs is a critical component of tests to ensure injectable medications such as coronavirus vaccines aren’t contaminated.
To obtain it, harvesters bring many thousands of the creatures to laboratories to be bled each year, and then return them to the sea — a practice that has drawn criticism from conservationists because some don’t survive the process.
The blood, which is blue due to its copper content, is coveted for proteins used to create the LAL test, a process used to screen medical products for bacteria. Synthetic alternatives aren’t widely accepted by the health care industry and haven’t been approved federally, leaving the crabs as the only domestic source of this key ingredient.
Many of these crabs are harvested along the coast of South Carolina, where Gov. Henry McMaster promoted the niche industry as key to the development of a domestic medical supply chain, while also noting that environmental concerns should be explored.