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Test Code AGABS Alpha-Galactosidase, Blood Spot

Reporting Name

Alpha-Galactosidase, BS

Useful For

Diagnosis of Fabry disease in male patients using blood spot specimens

 

Verifying abnormal serum alpha-galactosidase results in male patients with a clinical presentation suggestive of Fabry disease

 

Follow-up to an abnormal newborn screen for Fabry disease

Testing Algorithm

The following algorithms are available in Special Instructions:

-Fabry Disease Testing Algorithm

-Fabry Disease: Newborn Screen-Positive Follow-up

 

For more information, see Newborn Screening Act Sheet Fabry Disease: Decreased Alpha-Galactosidase A in Special Instructions.

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Specimen Type

Whole blood


Advisory Information


This test is not suitable for carrier detection in females. It is recommended that molecular testing (FABRZ / Fabry Disease, Full Gene Analysis, Varies) be performed for diagnosis in females.



Additional Testing Requirements


Additional studies including molecular genetic analysis of the GLA gene (FABRZ / Fabry Disease, Full Gene Analysis, Varies) are recommended to detect carriers.

 

Pseudodeficiency results in low measured alpha-galactosidase A, but is not consistent with Fabry disease; FABRZ / Fabry Disease, Full Gene Analysis, Varies should be performed to resolve the clinical question.



Necessary Information


Provide a reason for referral with each specimen.



Specimen Required


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

Container/Tube:

Preferred: Blood spot collection card

Acceptable: Ahlstrom 226 filter paper and Whatman Protein Saver 903 Paper

Specimen Volume: 2 blood spots

Collection Instructions:

1. Do not use device or capillary tube containing EDTA to collect specimen.

2. An alternative blood collection option for a patient >1 year of age is fingerstick.

3. Let blood dry on the filter paper at ambient temperature in a horizontal position for 3 hours.

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

5. Do not stack wet specimens.

6. Keep specimen dry.

Additional Information:

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

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


Specimen Minimum Volume

Blood spot: 1

Specimen Stability Information

Specimen Type Temperature Time Special Container
Whole blood Ambient (preferred) 90 days FILTER PAPER
  Frozen  90 days FILTER PAPER
  Refrigerated  90 days FILTER PAPER

Reference Values

Males: ≥1.2 nmol/mL/hour

Females: ≥2.8 nmol/mL/hour

An interpretive report will be provided.

Day(s) and Time(s) Performed

Varies

Test Classification

This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the U.S. Food and Drug Administration.

CPT Code Information

82657

LOINC Code Information

Test ID Test Order Name Order LOINC Value
AGABS Alpha-Galactosidase, BS 55908-8

 

Result ID Test Result Name Result LOINC Value
50883 Specimen 31208-2
50884 Specimen ID 57723-9
50885 Source 31208-2
50886 Order Date 82785-7
50887 Reason For Referral 42349-1
50888 Method 49549-9
50889 Alpha-Galactosidase, BS 55908-8
50890 Interpretation 59462-2
50891 Amendment 48767-8
50892 Reviewed By 18771-6
50893 Release Date 82772-5

Reject Due To

Blood spot Shows serum rings or has multiple layers

Method Name

Fluorometric Enzyme Assay

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 in Special Instructions:

-Informed Consent for Genetic Testing (T576)

-Informed Consent for Genetic Testing-Spanish (T826)

2. Biochemical Genetics Patient Information (T602) in Special Instructions.

3. If not ordering electronically, complete, print, and send an Inborn Errors of Metabolism Test Request (T798) with the specimen.