The impact of non-endotoxin LAL-reactive materials on Limulus amebocyte lysate analyses

Limulus amebocyte lysate (LAL) is activated by bacterial endotoxins and certain glucans (beta-D-glucan, LAL-RM). The potential for conflicting inter-laboratory results for LAL tests exists because commercial LAL reagents are highly variable in response to LAL-reactive glucans. The nature of beta-D-glucan activation of LAL and means for rendering LAL non-responsive to glucan are reviewed to provide a background for resolving conflicting data. Kinetic LAL methods are particularly useful for screening materials potentially contaminated with glucan. The presence of beta-D-glucan in parenterals is uncommon and is likely limited to products exposed to microbial or cellulosic materials. A scheme is suggested for identifying LAL-reactive glucans and for LAL release-testing without glucan interference.