Human thyroglobulin reference material (CRM 457). 2nd Part: Physicochemical characterization and certification

Area of Science:

• Biochemistry
• Clinical Chemistry
• Laboratory Medicine

Background:

• Accurate measurement of thyroglobulin (Tg) is crucial for diagnosing and monitoring thyroid disorders.
• Interlaboratory variability in Tg immunoassays can lead to inconsistent patient results.
• A well-characterized primary reference material is needed to standardize Tg measurements.

Purpose of the Study:

• To characterize and certify a purified human thyroglobulin (Tg) reference material.
• To establish a primary reference standard for calibrating working serum-based reference materials for Tg immunoassays.
• To reduce interlaboratory variability in Tg measurement methods.

Main Methods:

• Purification of human thyroglobulin.
• Physicochemical characterization using polyacrylamide gel electrophoresis and immunoblotting.
• Amino acid composition analysis.
• Iodine content determination.
• Mass concentration determination using the Lowry method, supported by nitrogen determination, absorbance measurement, and amino acid analysis.

Main Results:

• The purified Tg exhibited the expected molecular size (660 kDa) with minor lower molecular weight forms.
• Amino acid composition aligned with cDNA data.
• Iodine content indicated moderate to high iodination.
• Certified mass concentration of the reference material (RM 457) is (0.324 +/- 0.018) g/L.

Conclusions:

• A certified human thyroglobulin reference material has been established.
• This reference material is a critical step towards reducing interlaboratory variability in Tg assays.
• Standardization of Tg measurements will improve diagnostic accuracy and patient management.