Creatine Biosynthesis Disorders: Creatine/GAA Analysis (Urine)

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.

Turnaround Time

2 weeks

CPT Code(s)

82542

Cost

$200

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.

Analysis will be done by tandem mass spectrometry (MS-MS) with quantitation of creatine, GAA, and creatinine (for urine samples).

Urine (at least 1 ml) is requested for the analysis. A fasting sample or first morning urine is preferred in males under 10 years of age.

Samples must be frozen and shipped on dry ice by overnight delivery services