Creatine Disorders Panel, Plasma
Use
The test is useful for evaluating patients with a clinical suspicion of arginine:glycine amidinotransferase deficiency, guanidinoacetate methyltransferase deficiency, and creatine transporter deficiency using plasma specimens. Depletion of cerebral creatine occurs in these conditions, and measurement of guanidinoacetate, creatine, and creatinine, along with associated analyte ratios in plasma and urine, aids in distinguishing the types of creatine deficiency syndromes. Treatment with oral creatine supplementation is effective in some cases and can impact test results.
Special Instructions
Not provided.
Limitations
Creatine supplementation may impact reliability of test results. The diagnosis of certain creatine synthesis disorders may not be conclusive without additional molecular analysis.
New York Approved
Methodology
Mass Spectrometry (LC-MS/MS)
Biomarkers
Result Turnaround Time
2-5 days
Related Documents
For more information, please review the documents below
Specimen
Plasma
Volume
0.5 mL
Minimum Volume
0.1 mL
Container
Lavender top (EDTA) preferred. Acceptable: Green top (sodium heparin), yellow top (ACD).
Collection Instructions
Centrifuge and aliquot plasma into a plastic vial. Send plasma frozen.
Storage Instructions
Send plasma frozen.
Causes for Rejection
Gross hemolysis, lipemia, icterus acceptable.
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 72 hours |
| Refrigerated | 7 days |
| Frozen | 14 days |