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Test Code AGAS Alpha-Galactosidase, Serum

Reporting Name

Alpha-Galactosidase, S

Useful For

Diagnosis of Fabry disease in male patients

 

Preferred screening test (serum) for Fabry disease

 

This test is not useful for patients undergoing a work up for a meat or meat-derived product allergy.

Testing Algorithm

The following algorithms are available:

-Fabry Disease: Newborn Screen-Positive Follow-up

-Fabry Disease Diagnostic Testing Algorithm

 

If the patient has abnormal newborn screening results for Fabry disease, refer to the appropriate ACMG Newborn Screening ACT Sheet.(1)

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Specimen Type

Serum


Ordering Guidance


If testing needed for assessment of meat or meat-derived product allergy, order either ALGAL / Galactose-Alpha-1,3-Galactose (Alpha-Gal), IgE, Serum or APGAL / Galactose-Alpha-1,3-Galactose (Alpha-Gal) Mammalian Meat Allergy Profile, Serum.

 

Carrier detection using enzyme levels is unreliable for female patients as results may be within the normal values. For testing carrier status, order FABRZ / Fabry Disease, Full Gene Analysis, Varies.



Additional Testing Requirements


Urine sediment analysis for the accumulating trihexoside substrate and measurement of globotriaosylsphingosine are recommended. Order both CTSU / Ceramide Trihexosides and Sulfatides, Random, Urine and LGB3S / Globotriaosylsphingosine, Serum.



Necessary Information


Sex of patient is required for interpretation of results.



Specimen Required


Collection Container/Tube:

Preferred: Serum gel

Acceptable: Red top

Submission Container/Tube: Plastic vial

Specimen Volume: 2 mL

Collection Instructions: Centrifuge and aliquot serum into a plastic vial.


Specimen Minimum Volume

0.3 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Serum Frozen (preferred) 14 days
  Refrigerated  24 hours

Reference Values

0.074-0.457 U/L

 

Note: Results from this assay are not useful for female carrier determination. Carriers usually have levels in the normal range.

Day(s) Performed

Tuesday, Friday

Test 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

82657

LOINC Code Information

Test ID Test Order Name Order LOINC Value
AGAS Alpha-Galactosidase, S 1813-5

 

Result ID Test Result Name Result LOINC Value
50590 Alpha-Galactosidase,S 1813-5
50584 Interpretation 59462-2
50586 Reviewed By 18771-6

Interpretation

Deficiency (<0.016 U/L) of alpha-galactosidase in properly submitted specimens is diagnostic for Fabry disease in male patients. If concerned about specimen integrity, recheck using leukocyte testing (AGAW / Alpha-Galactosidase, Leukocytes).

Clinical Reference

1. ACMG Newborn Screening ACT Sheets. Accessed October 30, 2023. Available at www.acmg.net/ACMG/Medical-Genetics-Practice-Resources/ACT_Sheets_and_Algorithms/ACMG/Medical-Genetics-Practice-Resources/ACT_Sheets_and_Algorithms.aspx?hkey=9d6bce5a-182e-42a6-84a5-b2d88240c508

2. Desnick RJ, Ioannou YA, Eng CM: Alpha-galactosidase A deficiency: Fabry disease. In: Valle D, Antonarakis S, Ballabio A, Beaudet AL, Mitchell GA, eds. The Online Metabolic and Molecular Bases of Inherited Disease. McGraw-Hill; 2019. Accessed October 30, 2023. Available at https://ommbid.mhmedical.com/content.aspx?sectionid=225546984

3. Mehta A, Hughes DA. Fabry Disease. In: Adam MP, Feldman J, Mirzaa GM, et al., eds. GeneReviews. Seattle (WA): University of Washington, Seattle; August 5, 2002

4. Laney DA, Bennett RL, Clarke V, et al. Fabry disease practice guidelines: Recommendations of the National Society of Genetic Counselors. J Genet Couns. 2013;22(5):555-564. doi: 10.1007/s10897-013-9613-3

5. Laney DA, Peck DS, Atherton AM, et al. Fabry disease in infancy and early childhood: a systematic literature review. Genet Med. 2015;17(5)323-330. doi: 10.1038/gim.2014.120

6. Ferreira S, Auray-Blais C, Boutin M, et al. Variations in the GLA gene correlate with globotriaosylceramide and globotriaosylsphingosine analog levels in urine and plasma. Clin Chim Acta. 2015;447:96-104. doi: 10.1016/j.cca.2015.06.003

7. Nowak A, Beuschlein F, Sivasubramaniam V, Kasper D, Warnock DG. Lyso-Gb3 associates with adverse long-term outcome in patients with Fabry disease. J Med Genet. 2022;59(3):287-293. doi: 10.1136/jmedgenet-2020-107338

Report Available

2 to 5 days

Method Name

Fluorometric

Forms

1. New York Clients-Informed consent is required. Document on the request form or electronic order that a copy is on file. The following documents are available:

-Informed Consent for Genetic Testing (T576)

-Informed Consent for Genetic Testing-Spanish (T826)

2. Biochemical Genetics Patient Information (T602)

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