| Laboratory: | Clinical Biochemistry |
| Test Name: |
CREATINE BIOSYNTHESIS & TRANSPORT DISORDERS - (U)
Test Code:
GAAU
|
| Clinical Information: |
Test Indications: 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.
Analysis is performed by tandem mass spectrometry (MS-MS) with quantitation of creatine, GAA, and creatinine. |
| Collection Devices: |
Preferred Device:
|
| Specimen Required: |
Urine: 5.0 mL
Pediatric Urine: 1.0 mL
A fasting urine sample or first morning urine is preferred in males under 10 years of age. |
| Referral: |
Urine: 5.0 mL
Pediatric Urine: 1.0 mL
Store and ship urine specimen frozen.
|
| Requisition: | |
| Reference Values: |
Three inherited disorders are known:
AGAT (L-arginine:glycine amidinotransferase)deficiency is autosomal recessive and shows low Guanidinoacetate (GAA). GAMT (guanidinoacetate methyltransferase)deficiency is autosomal recessive and shows elevated GAA. CTD (creatine transporter deficiency)is X-linked and shows elevated urinary creatine/creatinine ratio. An interpretation of results will be included on the report. |
| Availability: |
Within 3 Weeks
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| See Also: | |
| More Information: |
Testing is performed at Greenwood Genetic Center, 101 Gregor Mendel Circle, Greenwood, SC 29646. Phone: (864) 941-8100
See: http://www.ggc.org/diagnostics/biochemical/creatine.htm |