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Method: GC-MS (Gas Chromatography/Mass Spectrometry) measuring organic acid metabolites in urine (CLIA 17D0919496); not cleared or approved by the FDA. Results in mmol/mol creatinine. Not a stand-alone diagnosis; should be interpreted in clinical context.
4-Hydroxybutyric acid sits at a junction between amino-acid handling and nervous-system chemistry, normally present at low levels.
