Metrology for accurate protein quantification and precision diagnostics

Amandine Boeuf
Laboratoire National de Métrologie et d’Essais, département Bioanalyses, Paris, France

Amandine Boeuf (Presenter) Laboratoire National de Métrologie et d'Essais

Relevant Financial Disclosures (within past 24 months, reported on May 21, 2026) No relevant financial relationship(s) to disclose.

Proteins are dynamic and heterogeneous biomolecules that may serve as clinical biomarkers for disease prognosis, diagnosis, and monitoring. Numerous assays, primarily immunoassays, with various measurement principles, have been developed to detect or quantify proteins. Thus, reliable detection, accurate quantification, and comparability of measurement results in biological matrices are essential for the healthcare and safety of patients.

A proven way to achieve reliable quantitative results is to establish metrological traceability to the International System of Units (SI). SI-traceable reference measurement procedures (RMPs) have been developed for the purity assessment of peptide and protein materials as well as for their quantification in biological matrices. These RMP mainly rely on the Isotope Dilution Mass Spectrometry (IDMS) approach, where a known amount of stable isotope-labelled internal standard is added to the sample, and the signal ratio of the unlabelled analyte to the labelled internal standard allows absolute quantification of proteins.

Until now, most of these RMPs determine the protein content based on the primary structure of proteins, and no metrological tools are available for the SI-traceable quantification of modified proteins, proteoforms, or proteins’ higher-order structure. However, modifications of the primary structure and the presence of proteoforms may affect and bias the protein quantification, depending on which form is intended to be measured. To ensure the reliability of measurements, it is crucial to develop metrological references to unravel protein overall structures, interactions, and the structure-function relationship. The EU-funded ProMET project, gathering metrology institutes with the proteomics, structural, and systems biology communities, intends to address these fundamental metrology challenges by investigating the protein structures using MS, biophysical approaches, and computational techniques, and the influence of heterogeneity on quantitative measurements.