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HelpOrder Code HGEMP Hydroxyglutaric Acids, Glutaric Acid, Ethylmalonic Acid, and Methylsuccinic Acid, Plasma
Useful For
Evaluation of patients with an abnormal newborn screen showing elevations of glutarylcarnitine (C5-DC) using plasma specimens
Evaluation of patients with abnormal newborn screens showing elevations of C4- acylcarnitine to aid in the differential diagnosis of short chain acyl-CoA dehydrogenase and isobutyryl-CoA dehydrogenase deficiencies
Diagnosis of glutaric acidemia type 1
Aiding in diagnosis of glutaric acidemia type 2
Genetics Test Information
Second-tier newborn screening for follow-up of C4 acylcarnitine and glutarylcarnitine (C5DC) elevations.
Differentiating diagnoses of short chain acyl-CoA dehydrogenase (SCAD) deficiency, isobutyryl-CoA dehydrogenase (IBDH) deficiency, and ethylmalonic encephalopathy.
Differentiating diagnoses of glutaric acidemia type I (GA-1) and glutaric acidemia type II (GA-2)
Method Name
Liquid Chromatography Tandem Mass Spectrometry (LC-MS/MS)
Reporting Name
HGEM, PSpecimen Type
PlasmaNecessary Information
Patient's age is required.
Specimen Required
Supplies: Sarstedt Aliquot Tube, 5 mL (T914)
Collection Container/Tube:
Preferred: Green top (sodium heparin)
Acceptable: Lavender top (EDTA), green top (lithium heparin)
Submission Container/Tube: Plastic vial
Specimen Volume: 0.1 mL
Collection Instructions: Centrifuge and aliquot plasma into a plastic vial.
Specimen Minimum Volume
0.02 mL
Specimen Stability Information
| Specimen Type | Temperature | Time |
|---|---|---|
| Plasma | Refrigerated (preferred) | 90 days |
| Frozen | 90 days | |
| Ambient | 12 days |
Reject Due To
| Gross hemolysis | OK |
| Gross lipemia | OK |
| Gross icterus | OK |
Reference Values
2-OH Glutaric acid ≤4.5 nmol/mL
3-OH Glutaric acid ≤0.7 nmol/mL
Glutaric acid ≤0.8 nmol/mL
Methylsuccinic acid ≤0.3 nmol/mL
Ethylmalonic acid ≤1.5 nmol/mL
Method Description
An aqueous internal standard is added to the specimen. The supernatant is evaporated under heated nitrogen, and the residue is then reconstituted prior to injection onto a liquid chromatography tandem mass spectrometry (LC-MS/MS). The ratios of the extracted peak areas of glutaric acid, ethylmalonic acid, and methylsuccinic acid to their respective internal standards as determined by LC-MS/MS are used to calculate the concentration of each analyte in the sample.(Unpublished Mayo method)
Day(s) Performed
Monday, Wednesday
Performing Laboratory
Mayo Clinic Laboratories in Rochester
CPT Code Information
83918
Forms
If not ordering electronically, complete, print, and send a Biochemical Genetics Test Request (T798) with the specimen.