Saline and buffers minimize the action of interfering factors in the bacterial endotoxins test.

The bacterial endotoxins test (BET) is the most sensitive assay for measuring endotoxin levels in solution. However, it is difficult to quantify endotoxin levels in some solutions because unknown interfering factors may inhibit or enhance the Limulus amebocyte lysate (LAL) coagulation reaction. We investigated the mechanisms of this interference and found that interference can be reduced or totally suppressed by preparing sample solutions in saline, Dulbecco's phosphate-buffered saline (D-PBS), N,N-bis-(2-hydroxyethyl)-2-aminoethanesulfonic acid (BES), or 2-amino-2-hydroxymethyl-1,3-propanediol (Tris) buffers.