Development of commutable candidate certified reference materials from protein solutions: concept and application to...

Area of Science:

• Biochemistry
• Analytical Chemistry
• Clinical Diagnostics

Background:

• Protein reference materials (RMs) are crucial for standardizing in vitro diagnostics.
• Lack of commutability in current protein RMs hinders accurate clinical test results.
• Human insulin (hINS) is a key analyte requiring standardized measurement.

Purpose of the Study:

• To investigate and overcome factors limiting commutability in protein solution RMs.
• To develop commutable hINS solution reference materials for improved diagnostic accuracy.
• To establish a novel concept for creating standardized protein RMs.

Main Methods:

• Developed a concept involving matrix matching, structural analysis, and higher-order structure adjustment.
• Constructed hINS-Zn2+ aggregates in vitro, confirmed by spectroscopy and mass photometry.
• Measured active concentration via surface plasmon resonance and verified commutability using CLSI EP14 and IFCC methods.

Main Results:

• Developed six levels of hINS solution candidate certified RMs (cCRMs) with excellent homogeneity and stability (>6 months at -70°C).
• Achieved relative uncertainties between 4.0% and 5.0% for the cCRMs.
• Demonstrated good commutability across routine chemiluminescent immunoassay systems.

Conclusions:

• Successfully applied a new concept for developing commutable RMs using pure protein material.
• The developed hINS solution cCRMs address challenges in matrix-based RMs.
• This approach contributes significantly to the standardization of protein test results in clinical settings.