Multiplexed LC-MS/MS assay for urine albumin.

Area of Science:

• Clinical Chemistry
• Analytical Chemistry
• Biomarker Measurement

Background:

• Urine albumin is a key indicator for renal dysfunction and cardiovascular disease.
• Accurate urine albumin measurement is vital for clinical diagnosis.
• Current methods lack a validated reference system, hindering accuracy assessments.

Purpose of the Study:

• To develop a candidate reference measurement procedure for urine albumin.
• To establish a reliable reference system for accurate urine albumin quantification.
• To address the need for improved diagnostic accuracy in renal and cardiovascular disease assessment.

Main Methods:

• Utilized isotope dilution-mass spectrometry (ID-MS) with multiple reaction monitoring (MRM).
• Employed a targeted mass spectrometric approach for full-length urine albumin quantification.
• Incorporated isotopically labeled ((15)N) recombinant human serum albumin as an internal standard for absolute quantitation.

Main Results:

• Developed and validated a candidate reference measurement procedure for urine albumin.
• Quantified albumin in pooled human urine samples using the developed ID-MS/MRM method.
• Demonstrated the accuracy of the mass spectrometry-based urine albumin quantitation method.

Conclusions:

• The developed ID-MS/MRM procedure serves as a candidate reference measurement system for urine albumin.
• This advancement enables more accurate quantification of urine albumin, improving diagnostic capabilities.
• Establishes a foundation for accurate clinical diagnosis and prognostic assessment of renal and cardiovascular conditions.