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Special Instructions
This assay currently is not available in New York state.
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This assay |
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This assay currently is not available in New York state. |
Expected Turnaround Time
10 - 14 days
Turnaround time is defined as the usual number of days from the date of pickup of a specimen for testing to when the result is released to the ordering provider. In some cases, additional time should be allowed for additional confirmatory or additional reflex tests. Testing schedules may vary.
Specimen Requirements
Specimen
Urine, frozen
Volume
1.0 mL
Minimum Volume
0.5 mL
Container
Sterile cup
Storage Instructions
Freeze as soon as possible after collection; ship within 24 hours.
Stability Requirements
| Temperature | Period |
|---|---|
| Room temperature | Unstable (stability provided by manufacturer or literature reference) |
| Refrigerated | Unstable (stability provided by manufacturer or literature reference) |
| Frozen | Indefinite (stability provided by manufacturer or literature reference) |
Causes for Rejection
Thawed sample
Test Details
Use
Urine Alpha aminoadipic semialdehyde (AASA) is useful for diagnosing pyridoxine-dependent seizures (PDS) and folinic acid-responsive seizures (FRS). Elevation of AASA can also occur in molybdenum cofactor deficiency. Urine AASA may also be used for assessment of Variants of Uncertain Significance (VUS) identified during genetic testing (e.g. Next Generation Sequencing or Capillary Sequencing Testing). Pyridoxine dependent seizures is a genetic disorder characterized by seizures in neonates or infants up to 3 years of age, which in general, respond to a pharmacologic dose of pyridoxine (vitamin B6). AASA dehyrogenase (antiquin) deficiency is the underlying defect. Piperideine-6-Carboxylate (P6C) is the cyclic isomer of AASA and the equilibrium between P6C and AASA is PH dependent. P6P reacts with pyridoxal 5'-phosphate and leads to deficiency of this cofactor. Folinic responsive seizures and PDS are allelic, and caused mutations in the ALDH7A1 gene. Biochemical testing should be done prior to gene sequencing, and can be done regardless of pyridoxine therapy.
Limitations
This test was developed and its performance characteristics determined by LabCorp. It has not been cleared or approved by the Food and Drug Administration.
Methodology
Liquid chromatography/tandem mass spectrometry (LC/MS-MS)
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