Why bacterial endotoxin test is also called LAL test?

Bacterial endotoxin test (BET) is very important test and one of the important release criteria of injectable finished product into the market. Earlier bacterial endotoxin toxin test was called as LAL test.

 

What is the meaning of LAL test?

Here, LAL means Limulus amoebocyte lysate. Amoebocyte cells are purified from the blood of the horse shoe crab. These amoebocyte cells have special property that when they comes in contact with the endotoxin released by gram negative bacteria, it forms a clot. This concept is used in bacterial endotoxin test. There are currently four species of horse shoe crab.

a) Limulus polyphemus is found in the eastern coast of North and Central America. The size of the limulus polyphemus is big as compare to other three species. The name of LAL test come from the use of amoebocyte cell of limulus polyphemus which is also called lysate and here comes the name "LAL".

                                               Limulus Polyphemus

b) Carcinoscorpius rotundicauda is found in Indo Pacific region. Amoebocyte cells are also used from this species and it is also called CAL test.

                                             Carcinoscorpius rotundicauda

c) Tachypleus tridentatus is also found in Indo Pacific region. Amoebocyte cells are also used from this species and it is also called TAL test.

                                                  Tachypleus tridentatus

d) Tachypleus gigas is also found in Indo Pacific region. 

                                                      Tachypleus gigas

These are four species of horse shoe crab. But most commonly species of horse shoe carb is Limulus polyphemus which is widely used in India as well. However TAL (Tachypleus amoebocyte lysate) is generally used in China.

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