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HelpTest Code HGEMP Hydroxyglutaric Acids, Glutaric Acid, Ethylmalonic Acid, and Methylsuccinic Acid, Plasma
Reporting Name
HGEM, PPerforming Laboratory
Mayo Clinic Laboratories in Rochester
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
Method Name
Liquid Chromatography Tandem Mass Spectrometry (LC-MS/MS)
Necessary Information
Patient's age is required.
Specimen Required
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 Type
PlasmaSpecimen Minimum Volume
0.02 mL
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| 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
Interpretation
Elevations of ethylmalonic acid (EMA) and methylsuccinic acid (MSA) are consistent with a diagnosis of short chain acyl Co-A dehydrogenase (SCAD) deficiency.
Elevation of EMA is consistent with a diagnosis of ethylmalonic encephalopathy.
Normal levels of EMA in the context of elevated C4 is consistent with a diagnosis of isobutyryl-CoA dehydrogenase (IBDH) deficiency.
Elevation of glutaric acid (GA) and 3-hydroxyglutaric acid (3OH-GA) are consistent with a diagnosis of glutaric acidemia type I (GA1).
Elevation of GA, 2-hydroxyglutaric acid (2OH-GA), 3OH-GA, EMA, and MSA are consistent with a diagnosis of glutaric acidemia type II (GA2).
Day(s) Performed
Monday, Wednesday
Report Available
3 to 7 daysTest Classification
This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. It has not been cleared or approved by the US Food and Drug Administration.CPT Code Information
83918
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| HGEMP | HGEM, P | 92673-3 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| 36062 | 2-OH Glutaric acid | 69845-6 |
| 36063 | 3-OH Glutaric acid | 69851-4 |
| 36064 | Glutaric acid | 27301-1 |
| 36065 | Methylsuccinic acid | 69829-0 |
| 36066 | Ethylmalonic acid | 79476-8 |
| 36067 | Interpretation (HGEMP) | 59462-2 |
| 36068 | Reviewed By | 18771-6 |
Forms
If not ordering electronically, complete, print, and send a Biochemical Genetics Test Request (T798) with the specimen.