MetaSign : Metabolomic Profiling

Test Information

MetaSign is the GGC Diagnostic Lab's metabolomic signature test. The metabolomic signature represents 600-800 metabolites across various biochemical pathways. This screening test is a semi-quantitative assay identifying small molecules (between 50-1,500 Daltons (Da) in molecular weight) in patient plasma samples. Please note that since this is a screening test, any abnormalities identified on the MetaSign screen should be confirmed with follow-up testing. Sample quality, diet, supplementation, medications, and other physiological conditions impact metabolomic analysis and may result in false positive and false negative results. Therefore, disclosure of the patient's medical history, medications, and dietary supplements or restrictions is necessary for accurate interpretation. Please fill out complete information on the requisition form. Compounds related to diet, drugs and microbial metabolism will not be reported. A complete report can be provided upon request.

Turnaround Time

5 weeks

CPT Code(s)

84999

Cost

$1,000

Indications

MetaSign should be considered as a testing option in case of:

Developmental delay
Intellectual disability
Speech and/or language delay
Seizures/staring spells/abnormal movements
Cyclical vomiting
Hypoglycemia
Hypotonia
Failure to thrive
Autism spectrum disorder
Undifferentiated phenotype (possibly related to a biochemical pathway perturbation)
Equivocal molecular test results in genes involved in metabolism

Methodology

The analyte identification is performed using four different types of high-performance Ultra Performance Liquid Chromatography (UPLC) instruments paired with Mass Spectrometry (UPLC/ MS). The identification of each molecule is confirmed against a proprietary chemical library consisting of accurate molecular weight/mass, mass spectral fragmentation patterns, and additional reference data. Overall process variability is assessed using stable isotope standards to monitor the performance of the assay and for quality control purposes. The signal intensity of each metabolite in the panel is compared to its signal intensities from a reference cohort to calculate a Z-score that is representative of the standard deviations from the mean.

Limitations: MetaSign detects small molecules between 50-1,500 Daltons, and any metabolites beyond this size range such as proteins, oligosaccharides, glycosylation metabolites, and certain lipids will not be detected. This test may fail to detect some metabolites for various reasons including, but not limited to: a) the presence of an analyte below the detection level, b) interference from other metabolites and c) the need for special processing. Improper sample processing and handling can cause sample degradation and adversely impact the interpretation of data/results.

This test is performed in collaboration with Metabolon Inc., Durham, NC

Specimen Requirements

Required Specimen: EDTA Plasma specimen (must be STAT processed)

1.Draw blood (approximately 5 mL) into the lavender top, EDTA tube and gently invert 8-10 times to ensure mixing of anticoagulant (EDTA) with blood to prevent clotting.

2.Centrifuge EDTA tubes at 800-1800g for approximately 10 minutes to separate the plasma from the whole blood cellular fraction.

3.Important note: The plasma must be separated from the whole blood within 1 hour to obtain accurate test results.

4.Using a disposable pipette, transfer as much of the plasma as possible (minimum of 0.25 mL) into a screw-top cryogenic vial and cap the vial tightly. The plasma should be free of hemolysis and red blood cells.

5.Label the cryotube with the patient's name and date of birth.

6.Immediately place the plasma specimen into the freezer (< -20 C). Store the plasma specimen frozen until it is ready for shipment.

This test requires a STAT processed sample.

Transport Instructions

Specimens should remain frozen until time to ship or transport. Frozen plasma can be sent via courier or FedEx

Use an insulated shipping container with an inner-styrofoam cooler and outer cardboard shipping box. Specimen should be placed in shipping container with dry ice. Ship overnight.

Once the plasma has been removed and frozen, samples can be held for delayed shipping. We suggest holding specimens collected on Friday and shipping on Monday. Samples can be accepted on Saturday if necessary, but Saturday delivery should be avoided if possible.

Have Questions Need Support?

Call our laboratory at 1-800-473-9411 or contact one of our Laboratory Genetic Counselors for assistance.
Robin Fletcher, MS, CGC
Kellie Walden, MS, CGC

Analyte Analysis, Biochemical Testing, MetaSign
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