Specimen Collection
5 mL Urine (Random)
If a newborn urine collector is used to collect urine, the urine once collected in the urine bag must be transferred into a 50 mL yellow top urine jar without delay whilst ensuring protection from light.
Date of collection, time of collection, and if applicable "Pre BH4 load" or "Post BH4 load?"must be noted on the sample jar and the accompanying request form. Please fill in all details requested on the form - doing so will expedite reporting and a differential diagnosis.
Wrap container immediately in tinfoil and send to laboratory on ice.
Samples must be frozen immediately once receipted in the Laboratory.
Urine samples contaminated with blood or fecal matter are not accepted for testing. Recollect clean sample.
5 mL Urine (Random)
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5 mL Urine (Random)
If a newborn urine collector is used to collect urine, the urine once collected in the urine bag must be transferred into a 50 mL yellow top urine jar without delay whilst ensuring protection from light.
Date of collection, time of collection, and if applicable ?Pre BH4 load? or ?Post BH4 load? must be noted on the sample jar and the accompanying request form. Please fill in all details requested on the form ? doing so will expedite reporting and a differential diagnosis.
Wrap container immediately in tinfoil and send to laboratory on ice.
Samples must be frozen immediately once receipted in the Laboratory.
Urine samples contaminated with blood or faecal matter are not accepted for testing. Recollect clean sample.
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Reference Intervals
The reference interval will be provided with the result.
Turnaround Time: Between 5 weeks and 8 weeks
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Between 5 weeks and 8 weeks.
Unless urgent request received through pathologist or metabolic team.
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Assay Method
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Referred to NSW Biochemistry Westmead, Sydney
Liquid Chromatography Tandem Mass Spectrometry (LC-MS/MS) for Pterins, Biogenic Amine Metabolites and Creatinine.
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Diagnostic Use and Interpretation
Tetrahydrobiopterin is a cofactor for phenylalanine hydroxylase (and also tryptophan and tyrosine hydroxylases).
Urine pterins are no longer tested after a positive newborn screening test for phenylketonuria is encountered. A panel of PKU mutations is now requested by the Starship clinical metabolic service.
If there is a clinical requirement for urine pterin analysis, it must be approved by a Chemical Pathologist or Clinical Scientist in Biochemical Genetics. A special request form, attached to this test guide information, must be fully completed and must accompany the samples for analysis. This will assist with appropriate analysis and reporting times.
Download: Flowchart - Diagnostic flowchart for differential diagnosis of BH4Ds.pdf
Download: Request form - Urinary Pterins Request Form.pdf
Contact Information
For further information, contact laboratory: ext. 22016 or via Lablink
or, contact the Metabolic Physician-on-call: 09 367 0000
Specimen Transport Instructions for Referring Laboratories
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Random Urine -
Pterins are very unstable and must be collected in subdued light, wrapped in tinfoil at the bedside, frozen immediately and remain frozen until analysed.
Please inform laboratory on ext. 22016, by email:
biogen@adhb.govt.nz
or via LabLink of specimen transport arrangements and an
URGENT
sticker is recommended.
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