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Neopterin/Tetrahydrobiopterin (CSF)

CPT: 82542
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Special Instructions

This assay is available in New York State

Specimen Requirements


Cerebrospinal Fluid (CSF)


1.0 mL

Minimum Volume

0.5 mL


MNG supplied screw capped vial #3


Must be collected in tube 3 from supplied kit, Neopterin may be ordered if MNG collection kit not available

Storage Instructions

Freeze as soon as possible after collection

Stability Requirements

Room Temperature: Not stable; Refrigerated: 24 hours; Frozen: 72 hours @ -20C, Indefinitely @ -80C; Freeze/Thaw: None

Causes for Rejection

Bloody CSF; Received thawed; Improper collection tube

Test Details


CSF Neopterin/Tetrahydrobiopterin 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).

CLINICAL: 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. The pattern of the changes in CSF of neopterin and BH4 are characteristic for each of the individual disorders of tetrahydrobiopterin metabolism. Disorders of BH4 metabolism are characterized by a wide range of symptoms that may include developmental delay, mental disability, behavioral disturbances, dystonia, Parkinsonian symptoms, gait disturbances, speech delay, psychomotor delay and ptosis.



Recommended MNG Kits

CSF Collection Tubes (set of 5 tubes per kit)


Order Code Order Code Name Order Loinc Result Code Result Code Name UofM Result LOINC
620010 Neopterin_BH4 (CSF) 80168-8 620004 Neopterin Result 34146-1
620010 Neopterin_BH4 (CSF) 80168-8 620191 Tetrahydrobiopterin Result 59247-7
620010 Neopterin_BH4 (CSF) 80168-8 620005 Neopterin BH4 Interpretation 80173-8
620010 Neopterin_BH4 (CSF) 80168-8 630811 PDF 80563-0