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Test Code AASA Alpha-aminoadipic semi-aldehyde

Clinical System Name

Alpha-aminoadipic semi-aldehyde


Piperideine-6-carboxylic acid (P6C)



 This test is used to diagnose pyridoxine-dependent seizures (PDS)  

Sample Requirements

Specimen: Whole Blood

Container(s): Dark Green/Sodium Heparin or Lt. Green/Lithium Heparin Tube

Preferred Vol: 1.0 mL

Minimum Vol: 0.5 mL


Note: Serum is acceptable but not preferred. 

Processing Instructions

Reject due to: If sample is not spun and frozen within 1 hour of collection. 48 hr storage at -20 C is acceptable

Spin: Y


Temp: -70 C

Storage location: -70 C freezer


Off-site collection: Plasma must be frozen at -70 C within 1 hour of collection. Ship on dry ice.


Temperature Time
Room temp ≤1 Hr
Refrigerated ≤1 Hr
Frozen (-700C) 6 months



STAT Performed TAT
N Weekly 7-10 days


Contact the Biochemical Genetics Lab for requests outside of stated availability (206)987-2216.

Performing Laboratory

Seattle Children's Laboratory    


Department:  Biochemical Genetics

Phone Number: 206-987-2216



Reference Range

Age <1 month > 1 month
AASA (mcmol/L) <0.4 <0.3
P6C (mcmol/L) <0.8 <0.5



Method: Liquid chromatography-tandem mass spectrometry

Analytical Volume: 0.25 mL


CPT Codes



Biochemical Genetics Requisition


On the requisition include clinical information needed for appropriate interpretation.  (Age, gender, drug therapy, and family history)

Clinical Utility

This test determines α-AASA and P6C concentration in plasma and serum for diagnosis of pyridoxine dependent seizures (PDS) and folinic acid-responsive seizures (FRS). Pyridoxine dependent seizures is a genetic disorder characterized by seizures in neonates or infants up to 3 years of age, which respond to a pharmacologic dose of pyridoxine (vitamin B6). Alpha-aminoadipic semialdehyde dehydrogenase (antiquin) deficiency is the underlying defect. Folinic responsive seizures and PDS are allelic, and caused by mutations in the ALDH7A1 gene. Biochemical testing should be done prior to gene sequencing, and can be done regardless of pyridoxine therapy.