Plasma-Free Metanephrine and Normetanephrine Quantification for Clinical Applications Validated by Combining...

Area of Science:

• Clinical Chemistry
• Analytical Chemistry
• Mass Spectrometry

Background:

• Plasma-free metanephrines are key biomarkers for diagnosing catecholamine-secreting tumors.
• Accurate quantification of metanephrine and normetanephrine is crucial for clinical diagnosis.

Purpose of the Study:

• To develop and validate a sensitive and specific liquid chromatography-tandem mass spectrometry (LC-MS/MS) method.
• To quantify metanephrine and normetanephrine in human plasma for improved tumor diagnosis.

Main Methods:

• Solid-phase extraction using a weak cation-exchange mechanism.
• Liquid chromatography-tandem mass spectrometry (LC-MS/MS) for quantification.
• Validation according to FDA and CLSI guidelines.

Main Results:

• Excellent linearity (R² > 0.999) for metanephrine and normetanephrine.
• Method met accuracy, precision, and lower limit of quantification criteria.
• Minor matrix effects observed at lowest concentrations, with overall high reliability.

Conclusions:

• The developed LC-MS/MS method is sensitive, specific, and reproducible.
• The assay is suitable for routine clinical applications in diagnosing pheochromocytoma and paraganglioma.
• Potential for further optimization using matrix-matched calibration.