Bacterial Endotoxin Test: Importance and Calculation of Maximum Valid Dilution (MVD) Translated into Professional English

In the bacterial endotoxin test using the gel clot Limulus Amebocyte Lysate (LAL) assay, the Maximum Valid Dilution (MVD)​ is a critical calculated parameter. Its importance is multifaceted. Primarily, the MVD defines the maximum allowable dilution factor for a test sample that can be detected while avoiding matrix interference, thereby ensuring the validity of test results. Secondly, it serves as the essential link between the product's endotoxin limit (L), a clinical safety standard, and the labeled sensitivity (λ) of the LAL reagent, translating the standard into a practical laboratory dilution procedure. Furthermore, the MVD calculation is fundamental for determining the applicable range of the standard curve in quantitative methods (e.g., kinetic turbidimetric and chromogenic assays). An inaccurate or absent MVD can lead to false-negative results due to excessive dilution or false-positive/-negative results from insufficient dilution that fails to overcome interference, ultimately compromising the pyrogen safety assessment of pharmaceuticals, medical devices, and other products.