Faecal amino acids stability: investigating optimal sampling conditions for analysis.

Area of Science:

• Biochemistry
• Analytical Chemistry
• Biomarker Discovery

Background:

• Faecal amino acids show potential as non-invasive diagnostic biomarkers.
• The stability of faecal amino acids under various pre-analytical conditions requires thorough investigation.

Purpose of the Study:

• To assess the impact of storage conditions on faecal amino acid concentrations.
• To evaluate the influence of sampling site, freeze-thaw cycles, and the OMNImet®·GUT device on faecal amino acid stability.

Main Methods:

• Faecal samples from three donors were subjected to diverse pre-analytical treatments.
• Amino acid concentrations were quantified using targeted liquid chromatography-tandem mass spectrometry.

Main Results:

• Most amino acids demonstrated stability across different sampling sites and following freeze-thaw cycles.
• Storage at -20°C maintained amino acid integrity, while storage at 4°C and 20°C resulted in variations.
• The OMNImet®·GUT device showed inconsistent effects on amino acid stabilization.

Conclusions:

• Pre-analytical variables significantly affect faecal amino acid concentrations.
• Standardization of pre-analytical conditions is imperative for ensuring the reliability of faecal amino acids as biomarkers.