Comparison of Characteristics for Two Limulus Amoebocyte Lysate (LAL; KQCL and ENDOSAFE-MCS) and Two Recombinant Factor C (ENDOZYME II and ENDOLISA) Endotoxin Assays, Using Information from the Assay Manufacturers and from This Study
| KQCL | ENDOSAFE-MCS | ENDOZYME II | ENDOLISA | |
|---|---|---|---|---|
| Origin of reagent | Animal | Recombinant production | ||
| Lot-to-lot reproducibilitya | Biological variability | More reproducible than LAL method (no biological variability) | ||
| Assay range with maximum sensitivity (EU/mL)a | 50–0.005 | 0.5–0.005 | 50–0.005 | 500–0.05 |
| pH rangea | 6 to 8 | 6 to 8 | 4 to 9 | 4 to 9 |
| PPCb spike (EU/mL) | 0.50 | 0.78 (for the batch cartridge used) | 0.50 | 5.0 |
| Standard range | Performed manually | Integrated | Performed manually | Performed manually |
| Glucan reaction | False positive | No false-positive glucan reaction owing to the absence of factor G | ||
| Matrix effects | Enhancement (RSEc recovery) for Product B Inhibition for Product D | RSE recovery close to 100% for all products except Product B (enhancement for 2 assays out of 3) | Reduced matrix effects owing to shorter enzymatic reaction Enhancement (RSE recovery) for Product B Method less suitable for Product A, which contains proteases, owing to endotoxin masking during protease inactivation by heating | Reduced matrix effects owing to shorter enzymatic reaction and integrated wash step. Method less suitable for Product A, which contains proteases, owing to endotoxin masking during protease inactivation by heating |
| Equipment /software | ELX808/win KQCL v4.02 | ENDOSAFE-MCS/EndoScan v5.5.3 | FLX80/Gen v3.0 | Plate shaker Incubator 37 °CF LX800/Gen v3.0 |
| Time to result | 2 h | 20 min | 2 h | 3.5 h |
| Regulatory status | Pharmacopeia method | Pharmacopeia method | Alternative method | Alternative method |