Utility Of An Automatic Limulus Amebocyte Lysate Kinetic Turbidimetric Test For Endotoxin Screening Of Dialysate Samples

BACKGROUND: Endotoxin contamination of dialysate has serious adverse effects on patients undergoing hemodialysis. Therefore, endotoxin activity in dialysate is closely monitored. Limulus amebocyte lysate (LAL) has been used as a reagent to measure endotoxin activity. Here, we investigated the efficacy of an automatic LAL kinetic turbidimetric test (Toxinometer ET-mini) for screening endotoxin activity in dialysate. METHODS: In total, endotoxin activity was measured in 110 dialysate samples obtained from several sites within hemodialysis circuits between June 2012 and March 2018. The results were compared with those from a conventional chromogenic substrate LAL test conducted by a clinical examination laboratory. RESULTS: Both the automatic LAL test and the chromogenic substrate LAL test had a minimum detection level of 0.001 endotoxin units (EU)/mL. Endotoxin activity levels measured via the automatic LAL test showed a strongly positive correlation (concordance correlation coefficient: 0.9933; 95% CI: 0.9902-0.9954) and good agreement (mean difference: 0.00±0.01 EU/mL) with those obtained using the chromogenic substrate LAL test. CONCLUSION: The results suggest that the automatic LAL test may be useful for endotoxin activity screening in hemodialysis facilities.