Limulus amebocyte lysate

[1] The recombinant factor C (rFC) assay is a replacement of LAL and TAL based on a similar reaction.

[2] The American medical researcher Fred Bang reported in 1956 that gram-negative bacteria, even if killed, will cause the blood of the horseshoe crab to turn into a gel, a type of semi-solid mass.

After coagulation and subsequent gelling, the resulting gel is thought to contain bacterial infections in the animal's semi-closed circulatory system.

[3] Modern analysis of the lysate has led to understanding of this system of cascade, with multiple enzymes working in sequence to produce the gel.

[7] The blood cells are separated from the serum using centrifugation and are then placed in distilled water, which causes them to swell and burst ("lyse").

The primary application for LAL is the testing of parenteral pharmaceuticals and medical devices that contact blood or cerebrospinal fluid.

[9] The LAL cascade is also triggered by (1,3)-β-D-glucan, via a different Factor G. Both bacterial endotoxins and (1,3)-β-D-glucan are considered pathogen-associated molecular patterns, or PAMPs, substances which elicit inflammatory responses in mammals.

With reports of higher-than anticipated mortality rates[7] it has been considered more ethical to devise alternatives to the test.

[13] The adoption of the rFC test was slow, which began to change in 2012 when the US FDA and the European health ministry acknowledged it as an accepted alternative.