Creatine/GAA (guanidinoacetate) – Creatine Biosynthesis Disorders

Test description Creatine biosynthesis disorders can be separated based on urine testing for guanidinoacetate (GAA) and creatine. Patients with AGAT deficiency show a low urinary GAA level while patients with GAMT have an elevated GAA level.
Disease name Creatine biosynthesis disorders:
AGAT (L-arginine:glycine amidinotransferase) deficiency
GAMT (guanidinoacetate methyltransferase) deficiency
Clinical info Both AGAT and GAMT are autosomal recessive disorders and are characterized by intellectual disability, speech delay and epilepsy. GAMT deficiency can also present with a dystonic hyperkinetic movement disorder.
Methodology Analysis will be done by tandem mass spectrometry (MS-MS) with quantitation of creatine, GAA, and creatinine (for urine samples).
Associated Tests Biochemical and Molecular testing for X-linked creatine transporter deficiency is also available.
Specimen Requirements Urine (at least 500ul) is preferred for the analysis. A fasting sample or first morning urine is preferred in males under 10 years of age. Plasma can also be accepted.
Transport Urine samples must be frozen and shipped on dry ice by overnight delivery services. Plasma should be shipped overnight or spin down and send frozen.
Turnaround time 14 days
CPT Codes Urine samples 82570, 82540, 82543
Plasma sample 82540, 82543
Cost Urine - $150
Plasma - $108
Contact For further information contact Kellie King, MS or Tim Wood, PhD at 1-800-473-9411

Biochemical Lab

The Biochemical Lab provides diagnostic and screening tests for a variety of inherited metabolic disorders.

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