Monday - Friday, 0800 - 1700.
2 - 3 days.
1.0 mL (at least 2.0 mL preferred).
Random urine, morning specimen preferred. Freeze without preservative.
Interpretive Reference Range:
Normal < 4.7 mg/mg creatinine.
Useful, together with serum and urine amino acids, in localizing urea cycle defects. Increased in ornithine transcarbamylase (OTC) deficiency, citrullinemia, argininosuccinic acidemia,
HHH (hyperornithinemia-hyperammonemia-homocitrullinuria) syndrome, and hereditary orotic aciduria.
Stable isotope dilution gas chromatography-mass spectrometry (GC/MS).