Why is bacterial endotoxin tested separately?

Mass spectrometry measures mass-to-charge behavior, while chromatography separates and detects chemical species under defined conditions. Neither method is designed to quantify bacterial endotoxin, so an apparently strong result in one cannot stand in for the other.

An interpretable endotoxin report identifies the method, units, reporting limit, sample preparation or dilution, and relevant controls. Interference, inhibition or enhancement, and recovery controls matter because the sample matrix can affect the assay.