Development of human serum matrix-based unconjugated estriol-certified reference material by recommended ID-LC-MS/MS...

Area of Science:

• Clinical Chemistry
• Metrology
• Biochemistry

Background:

• Lack of traceability in commercial calibrator kits for unconjugated estriol (uE3) hinders standardization of clinical assays.
• Existing reference materials do not adequately ensure metrological traceability in laboratory medicine.

Purpose of the Study:

• To develop and certify human serum matrix-based unconjugated estriol (uE3) reference materials (RMs) with established traceability.
• To provide commutable secondary reference materials for standardizing clinical routine assays.

Main Methods:

• Preparation of five concentration gradients of uE3 in a human serum matrix.
• Certification of RMs using isotope dilution liquid chromatography-tandem mass spectrometry (ID-LC-MS/MS) reference method.
• Collaborative study involving nine accredited reference laboratories following ISO/WD 15725-1.

Main Results:

• Five certified uE3 RMs (GBW (E) 091048-091052) were established with SI-traceable values.
• RMs demonstrated satisfactory homogeneity and stability.
• Commutability was confirmed across the reference method and three routine immunoassay systems.

Conclusions:

• The developed human serum matrix-based uE3 RMs address the critical need for traceability and standardization in clinical assays.
• These RMs are essential for maintaining the integrity of the uE3 measurement chain, supporting accurate patient diagnosis.
• The availability of these secondary reference materials is crucial for resolving standardization issues in unconjugated estriol measurements.