Practical LC-MS/MS Method for 5-Hydroxyindoleacetic Acid in Urine

Area of Science:

• Clinical Chemistry
• Analytical Chemistry
• Mass Spectrometry

Background:

• Serotonin, produced by enterochromaffin cells, is overexpressed in carcinoid tumors.
• 5-hydroxyindoleacetic acid (5-HIAA) is the primary urinary metabolite of serotonin.
• 5-HIAA levels are crucial for diagnosing and monitoring carcinoid disease.

Purpose of the Study:

• To develop and validate a "dilute-and-shoot" liquid chromatography-tandem mass spectrometry (LC-MS/MS) method.
• To enable precise quantification of 5-HIAA in urine samples.
• To provide a reliable diagnostic tool for carcinoid tumors.

Main Methods:

• Urine samples were diluted and processed using an automated liquid handler.
• Chromatographic separation was performed on a reversed-phase column.
• Detection and quantification utilized a triple quadrupole mass spectrometer with electrospray ionization and multiple reaction monitoring.

Main Results:

• The method demonstrated excellent linearity, accuracy, and precision (CVs 0.8%-5.4%) within a 0.5-100 mg/L range.
• Results correlated highly with a comparative HPLC method (R=0.9876).
• Minimal interference was observed from endogenous compounds, vitamins, medications, and drugs.

Conclusions:

• A simple, cost-effective LC-MS/MS method for urinary 5-HIAA measurement was successfully developed.
• This assay provides a valuable clinical tool for assessing carcinoid tumors.
• The method offers reliable and accurate 5-HIAA quantification for patient management.