Sign in →

Test Code AGABS Alpha-Galactosidase, Blood Spot

Reporting Name

Alpha-Galactosidase, BS

Performing Laboratory

Mayo Clinic Laboratories in Rochester

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

 

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

Method Name

Fluorometric Enzyme Assay


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. Order FABRZ / Fabry Disease, Full Gene Analysis, Varies for testing carrier status.



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.

Necessary Information


Provide a reason for testing with each specimen.



Specimen Required


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

Container/Tube:

Preferred: Blood spot collection card

Acceptable: PerkinElmer 226 (formerly 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 older than 1 year is a fingerstick. For detailed instructions, see How to Collect Dried Blood Spot Samples.

3. Let blood dry on the filter paper at ambient temperature in a horizontal position for a minimum of 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, 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 Type

Whole blood

Specimen Minimum Volume

1 Blood spot

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

Reject Due To

Shows serum rings Multiple layers Reject

Reference Values

Males: ≥1.2 nmol/mL/hour

Females: ≥2.8 nmol/mL/hour

An interpretive report will be provided.

Interpretation

In male patients, results less than 1.2 nmol/mL/hour in properly submitted specimens are consistent with Fabry disease. Normal results (≥1.2 nmol/mL/hour) are not consistent with Fabry disease.

 

In female patients, normal results (≥2.8 nmol/mL/hour) in properly submitted specimens are typically not consistent with carrier status for Fabry disease; however, enzyme analysis, in general, is not sufficiently sensitive to detect all carriers. Because a carrier range has not been established in females, molecular genetic analysis of the GLA gene (FABRZ / Fabry Disease, Full Gene Analysis, Varies) should be considered when alpha-galactosidase A activity is less than 2.9 nmol/mL/hour, or if clinically indicated.

 

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

 

For more information see Fabry Disease Diagnostic Testing Algorithm.

Day(s) Performed

Thursday

Report Available

8 to 15 days

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
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 85069-3
50889 Alpha-Galactosidase, BS 55908-8
50890 Interpretation 59462-2
50891 Amendment 48767-8
50892 Reviewed By 18771-6
50893 Release Date 82772-5

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.

Testing Algorithm

This test provides diagnostic testing for male patients with positive newborn screen results, positive family history, or clinical signs and symptoms suspicious for Fabry disease.

 

The following algorithms are available:

-Fabry Disease Diagnostic Testing Algorithm

-Fabry Disease: Newborn Screen-Positive Follow-up

 

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