Specimen Collection
1 Spot Adult Guthrie Card (Random)
Or plasma if arranged with the metabolic physician on call (09 367 0000). Plasma is appropriate if the patient has symptoms consistent with MSUD. See Amino Acids - plasma.
1 Spot Paediatric Guthrie Card (Random)
Reference Intervals
The reference interval will be provided with the result.
Uncertainty of measurement: 14%
Turnaround Time: Between 2 days and 1 week
Test is available urgently, if required contact laboratory on ext. 22016 or via LabLink.
Assay Method
Waters Acquity Amino Acid Analyser.
Pre-column derivatisation with reverse phase separation.
Diagnostic Use and Interpretation
Phenylketonuria (PKU) is a rare disorder of phenylalanine metabolism.
Untreated it results in markedly elevated phenylalanine levels and slowly progressive mental retardation. In New Zealand, almost all children are screened for PKU by measuring the phenylalanine concentration in the neonatal blood spot (Guthrie card). This is a highly accurate test.
Patients with PKU require a specialised diet and regular monitoring of their phenylalanine levels. Patients (or parents) collect a few drops of blood onto a Guthrie card and send these to the Newborn Metabolic Screening programme by routine mail.
The results are posted (or occasionally phoned) to the patients and appropriate doctor. It may be appropriate for patients to have occasional full amino acid analysis and this should be discussed with Dr Callum Wilson, Ph 021 555 392 or Dr Emma Glamuzina, Ph 021 403 617
Contact Information
For further information contact laboratory: ext 22016 or via Lablink.
or, Dr Callum Wilson, Metabolic Physician: Ph 021 555 392
or, Dr Emma Glamuzina, Metabolic Physician: Ph 021 403 617
Specimen Transport Instructions for Referring Laboratories
Samples must be dry before being placed into plastic specimen bags.
Venous samples can be used by dripping onto the card from the syringe or a dropper.