Specimen Collection
Dried blood spot or plasma if arranged with the metabolic physician on call (Ph 09 367 0000). Plasma is appropriate if the patient has symptoms consistent with MSUD. See Amino Acids - plasma.
1 Spot Guthrie Card
Reference Intervals
The reference interval will be provided with the result.
UOM
14%
Turnaround Time: Between 2 days and 3 days
Test is available urgently if required contact laboratory on x22016 or via LabLink
Assay Method
Waters Acquity Amino Acid Analyser. Pre-column derivatisation with reverse phase separation
Diagnostic Use and Interpretation
Maple syrup urine disease (MSUD) is a rare disorder of branched chain amino acid metabolism. In the classical form it presents in the neonatal period with lethargy and coma. Children with mild variants of the condition may present with recurrent episodes of unwellness, unexplained vomiting, hypoglycaemia and/or developmental delay. Diagnosis is based on the finding of significantly raised branched chain amino acids (valine, leucine, isoleucine) in plasma. These are normally raised in conditions of fasting and care must be taken in the interpretation of results. In the intermittent 'mild' form of the disease they may be normal when the child is well. A highly specialised diet is used to treat these patients with the aim to keep the leucine level below 400 umol/l (reference interval 60-200). Plasma amino acids should be measured after consultation with the Metabolic Physician-on-call: Ph 09 367 0000 Newborn metabolic screening includes measurement of leucine in the dried blood spot for detection of MSUD. Patients with MSUD have treatment monitored by measurement of branched chain amino acids and occasionally essential amino acids also (see amino acids, plasma). Dried blood spots may be used for quantitative measurement of branched chain amino acids.
Contact Information
For further information contact laboratory: ext 22016 or via Lablink or, contact the Metabolic Physician-on-call: 09 367 0000