LC–MS Calibration in Bioanalysis: A Practical Guide

Accurate LC–MS calibration underpins reliable bioanalytical data across drug discovery and clinical development, yet calibration strategy selection is often underexplored. This article outlines practical considerations for external calibration, surrogate matrices, surrogate analytes, stable-isotope labelled (SIL) internal standards, and the Standard Addition Method (SAM), framed within ICH M10 expectations. Emphasis is placed on understanding matrix effects, maintaining analyte/SIL ratio stability, and scientifically justifying alternative calibration approaches while demonstrating equivalence and bias control.