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Order Code HGEM Hydroxyglutaric Acids, Glutaric Acid, Ethylmalonic Acid, and Methylsuccinic Acid, Blood Spot

Useful For

Evaluation of patients with an abnormal newborn screen showing elevations of glutarylcarnitine (C5-DC) using dried blood spot 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 Co-A 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, BS

Specimen Type

Whole blood


Necessary Information


Patient's age is required.



Specimen Required


Supplies: Card-Blood Spot Collection (Filter Paper) (T493)

Container/Tube:

Preferred: Card-Blood Spot Collection (Filter Paper) from heel or finger stick

Acceptable: PerkinElmer (formerly Ahlstrom 226) filter paper, Munktell filter paper, Whatman Protein Saver 903 paper, available newborn screening card, blood collected in tubes containing sodium heparin or EDTA and dried on filter paper

Specimen Volume: 2 Blood spots

Collection Instructions:

1. Do not use device or capillary tube containing ACD to collect specimen. Sodium heparin or EDTA are acceptable but must be spotted on card the same day as collected.

2. Completely fill at least 2 circles on the filter paper card (approximately 100 microliters blood per circle).

3. Let blood dry on filter paper at room temperature in a horizontal position for 3 or more hours.

4. Do not stack wet specimens.

5. Do not expose specimen to heat or direct sunlight.

6. Keep specimen dry.

Additional Information:

1. For collection instructions, see Blood Spot Collection Instructions.

2. For collection instructions in Spanish, see Blood Spot Collection Card-Spanish Instructions (T777).

3. For collection instructions in Chinese, see Blood Spot Collection Card-Chinese Instructions (T800).


Specimen Minimum Volume

1 Blood spot

Specimen Stability Information

Specimen Type Temperature Time Special Container
Whole blood Ambient (preferred) 123 days FILTER PAPER
  Frozen  123 days FILTER PAPER
  Refrigerated  123 days FILTER PAPER

Reject Due To

Shows serum rings
Insufficient specimen
Blood collected with ACD
Nonapproved filter paper		 Reject

Reference Values

2-OH Glutaric acid: ≤25 nmol/mL

3-OH Glutaric acid: ≤1.5 nmol/mL

Glutaric acid: ≤1.5 nmol/mL

Methylsuccinic acid: ≤0.45 nmol/mL

Ethylmalonic acid: ≤3.5 nmol/mL

Method Description

An aqueous internal standard is added to the specimen. The extract is evaporated and reconstituted prior to injection onto a liquid chromatography tandem mass spectrometry (LC-MS/MS) system. The ratios of the extracted peak areas of glutaric acid (GA), ethylmalonic acid (EMA), and methylsuccinic acid (MSA) 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

1. Biochemical Genetics Patient Information (T602)

2. If not ordering electronically, complete, print, and send a Biochemical Genetics Test Request (T798) with the specimen.