What is the role of calibrators in a quantitative LC-MS/MS method?

• A. Calibrators adjust the instrument temperature.
• B. Calibrators are used to validate mass accuracy.
• C. Calibrators provide known concentration references to construct a calibration curve for accurate quantification of analytes in patient samples.
• D. Calibrators replace the need for validation.

Answer: (C)

In quantitative LC-MS/MS, you need a calibration curve that links the detector signal to known concentrations. Calibrators are solutions with defined amounts of the analyte that are measured to generate this curve, showing how the instrument’s response changes with concentration across the assay’s range. Once the curve is established, the signals from patient samples are interpolated on that curve to yield accurate concentrations. Calibrators are often prepared in a matrix similar to the samples to account for matrix effects, and an internal standard may be added to correct for run-to-run variability, but the main role is to define the concentration–response relationship used for quantification. Temperature control and mass accuracy checks are separate considerations, and calibrators do not replace the broader validation process.