Objective:

To highlight the systematic misidentification of phenylacetylglutamine (PAGIn) as phenylacetylglycine (PAGly) in metabolomics studies, emphasizing its implications for clinical relevance.

Key Findings:

• PAG has been misidentified as PAGly in nearly half of NMR-based studies, raising concerns about the accuracy of metabolomic data.
• The misidentification is due to reliance on spectral databases and careless use of data, which can lead to incorrect biological interpretations.
• PAG is linked to cardiovascular risk in humans, making correct identification critical for clinical applications.

Interpretation:

The propagation of misidentification reflects broader issues in metabolomics, affecting the credibility of biomarker research and clinical applications, particularly in the context of emerging disease markers.

Limitations:

• Focus primarily on NMR methods, potentially overlooking similar issues in LC-MS workflows, which may also contribute to misidentifications.
• The study does not address all possible metabolites or species, which could limit the generalizability of the findings.

Conclusion:

Correcting misidentifications and validating biomarkers are essential for the credibility of metabolomics in clinical translation.