Non Invasive Urine Collection
Unlike blood specimen collection, collecting urine specimen is a non-invasive procedure which will not cause any harm or discomfort to your baby. As parents ourselves, we know how hard it is to see our babies in distress when getting their heel pricked for blood specimen.
More Accurate than a blood-based test
The human urine contains numerous water-soluble organic compounds that are end-products or by-products of cellular metabolism (also called “metabolites”). There are reportedly more than 3,000 detectable metabolites in human urine. As many metabolic disorders are organic acid disorders (also known as “organic acidemias”), they can be detected more accurately using urine, based on the abnormal excretion patterns of the metabolites as a result of faulty metabolism caused by the disorder. Because our kidneys can efficiently remove unwanted or toxic metabolites from the blood, such compounds are excreted in large amounts in the urine, but may not be found in significant concentrations in blood.1
The American College of Medical Genetics (ACMG) actually recommends urine organic analysis as the diagnosis step for many of metabolic disorder, should there be a positive newborn screening result using the dried blood spot analysed by tandem mass spectrometry (MS/MS).3,4
Footnote:
Ion ofm/z 177 at 4.8 min and that ofm/z 479 at 9.98 and 10.02 are due to 3-hydroxypropionate (di-TMS) and diastereomers of methylcitrate (tetra-TMS), respectively. The ion ofm/z327 at 11.8 min is due to n-heptadecanoate (mono-TMS) used as an internal standard: 50 nmole was spiked in 0.1 ml of urine or serum.
The American College of Medical Genetics (ACMG) actually recommends urine organic analysis as the diagnosis step for many of metabolic disorder, should there be a positive newborn screening result using the dried blood spot analysed by tandem mass spectrometry (MS/MS).3,4
Footnote:Ion ofm/z 177 at 4.8 min and that ofm/z 479 at 9.98 and 10.02 are due to 3-hydroxypropionate (di-TMS) and diastereomers of methylcitrate (tetra-TMS), respectively. The ion ofm/z327 at 11.8 min is due to n-heptadecanoate (mono-TMS) used as an internal standard: 50 nmole was spiked in 0.1 ml of urine or serum.
More Accurate than a blood-based test
Metascreen® is a highly reliable newborn screening test as it combines the following systems to detect metabolic disorders:
Gas Chromatography-Mass Spectrometry (GC-MS)
- FDA approved method for urinary detection of chemical substance (“analyte”);
- Gold standard for lipids, drug metabolites and environmental analysis;
- Detects more than 250 compounds for the screening of over 100 Inborn errors of metabolism (“IEMs”) from urine
- Chromatography separates potentially interfering compounds, such as drugs, also excreted in the urine, so the integrity of the test result is intact.
- Uses multiple analytes to detect one single metabolic disorder.
- Benchmarked against international and local database of normal samples for the identification of an abnormal case.
| Metabolic Disorder | Analytes used with GC-MS | Analytes used with other technology (e.g MS/MS) |
|---|---|---|
| Phenylketonuria (PKU) |
|
|
| Maple Syrup Urine Disease(MSUD) |
|
|
| Isovaleric acidemia (IVA) |
|
|
A simple urine test can identify metabolic disorders without causing any harm or discomfort to your baby. From your baby’s single urine specimen, more than 100 metabolic disorders from 9 groups of inborn errors of metabolism can be identified via Metascreen® using GC-MS. In comparison, dried blood spot screening using MS/MS can only detect less than 50 metabolic disorders.
Below is a complete list of the metabolic disorders that can be detected with Metascreen®.
Below is a complete list of the metabolic disorders that can be detected with Metascreen®.
- Acid and organic acid metabolism disorders
- Sugar metabolism disorders
- Fatty acid metabolism disorders
- Peroxisomal disorders
- Purine & pyrimidine metabolism disorders
- Lactic acid, hyperpyruvic acid metabolic disorders
- Other IEMs
For more information about the conditions, please visit the following websites:
American College of Medical Genetics and Genomics
Genetics Home Reference
Online Mendelian Inheritance in Man
Orphanet
PubMed
References:
- Bouatra S, Aziat F, Mandal R, et al. The Human Urine Metabolome. PLoS ONE 8(9): e73076. Doi: 10.1371/journal.pone.0073076.
- Kuhara T, Shinka T, Inoue Y, et al. Chromatography B, 731 (1999) 141-147.
- ACMG ACT Sheets and Confirmatory Algorithms.
https://www.acmg.net/ACMG/Resources/ACMG/Resources/ACT_Sheets_and_Confirmatory_Algorithms/ACT_sheets_Homepage.aspx?hkey=759c3556-90cb-42a7-ba8d-af07742bf941. Accessed on 24 January 2014. - ACMG Standards and Guidelines for Clinical Genetics Laboratories 2006 Edition. https://www.acmg.net/pages/acmg_activities/stds-2002/f.htm Accessed on 24 October 2016
