Test Details
Methodology
High-pressure liquid chromatography (HPLC)
Result 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.
Use
CSF Neopterin/Tetrahydrobiopterin (NC03) is useful for diagnosis of certain disorders of neurotransmitter metabolism. This testing 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). Tetrahydrobiopterin (BH4) serves as a cofactor for the hydroxylation of phenylalanine and in the biosynthesis of biogenic amines. Deficiency of BH4 may occur as a result of mutations causing a reduction in one of the three biosynthetic enzymes, guanosine triphosphate cyclohydrolase. 6-pyruvoyl-tetrahydropterin synthase, sepiapterin reductase, or the two regenerating enzymes, pterin-4-carbinolamine dehydratase, and dihydropteridine reductase. Defects in BH4 metabolism can result in hyperphenylalaninemia and deficiency of the neurotransmitters dopamine and serotonin. Changes in CSF neopterin may also occur in deficiency of the BH4 synthesis pathway. Disorders of BH4 metabolism are characterized by a wide range of symptoms that may include developmental delay, intellectual disability, behavioral disturbances, dystonia, Parkinsonian symptoms, gait disturbances, speech delay, psychomotor impairment and ptosis.
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.
Specimen Requirements
Specimen
Cerebrospinal fluid (CSF)
Volume
1.0 mL
Minimum Volume
0.5 mL
Container
Sterile screw capped vial
Collection Instructions
Sample must be collected in tube no. 3 from supplied kit (PeopleSoft No. 125218).
Stability Requirements
Temperature | Period |
|---|---|
Room temperature | Unstable (stability provided by manufacturer or literature reference) |
Refrigerated | 24 hours (stability provided by manufacturer or literature reference) |
Frozen | -20°C = 72 hours; -80°C = Indefinitely (stability provided by manufacturer or literature reference) |
Storage Instructions
Freeze as soon as possible after collection at -80°C.
Causes for Rejection
Bloody CSF; received thawed