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Test Code MPS4B Mucopolysaccharidosis IV Enzyme Panel, Blood Spot


Necessary Information


1. Patient's age is required.

2. Reason for testing is required



Specimen Required


Submit only 1 of the following specimen types:

 

Preferred:

Specimen Type: Blood spot

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

Container/Tube:

Preferred: Blood Spot Collection Card

Acceptable: Whatman Protein Saver 903 Paper, PerkinElmer 226 filter paper, Munktell filter paper, or blood collected in tubes containing ACD or EDTA and dried on filter paper.

Specimen Volume: 2 Blood spots

Collection Instructions:

1. 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.

2. At least 2 spots should be complete, ie, unpunched.

3. Let blood dry on filter paper at room 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.

Specimen Stability Information: Refrigerated (preferred) 60 days/Ambient 7 days/Frozen 60 days

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)

 

Acceptable:

Specimen Type: Whole Blood

Container/Tube:

Preferred: Lavender top (EDTA)

Acceptable: Yellow top (ACD)

Specimen Volume: 2 mL

Collection Instructions: Send whole blood specimen in original tube. Do not aliquot.

Specimen Stability Information: Refrigerate (preferred) 7 days/Ambient 48 hours


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.

Secondary ID

618294

Useful For

Supporting the biochemical diagnosis of mucopolysaccharidosis type IVA and IVB

 

This test is not useful for carrier detection.

Reflex Tests

Test ID Reporting Name Available Separately Always Performed
MPSBS Mucopolysaccharidosis, BS Yes No

Testing Algorithm

If results are normal, testing is complete.

 

If results indicate mucopolysaccharidoses IVA or IVB, quantitation of heparan sulfate, dermatan sulfate and keratan sulfate may be performed at an additional charge.

Method Name

Liquid Chromatography Tandem Mass Spectrometry (LC-MS/MS)

Specimen Type

Whole blood

Specimen Minimum Volume

Blood Spots: 1
Whole Blood: 0.5 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Whole blood Varies

Reject Due To

Blood spot specimen that shows serum rings or has multiple layers Reject
Insufficient specimen Reject
Unapproved filter papers Reject

Reference Values

N-acetylgalactosamine-6-sulfatase: >0.70 nmol/mL/hour

Beta-galactosidase: >1.30 nmol/mL/hour

 

An interpretive report will be provided.

Interpretation

Abnormal results are not sufficient to establish a diagnosis of a particular disease. To verify a preliminary diagnosis based on this assay, additional biochemical or molecular genetic analyses are required.

 

When abnormal results are detected, a detailed interpretation is given, including an overview of the results and of their significance, a correlation to available clinical information, elements of differential diagnosis, recommendations for additional biochemical testing, and in vitro, confirmatory studies (enzyme assay, molecular genetic analysis), and a phone number to reach one of the laboratory directors in case the referring physician has additional questions.

Method Description

One dried blood spot sample (DBS) is incubated with a mix of substrate and internal standard (IS) for iduronate 2-sulfatase, heparan N-sulfatase, alpha-N-acetylglucosaminidase, N-acetylgalactosamine-sulfate, beta-galactosidase, arylsulfatase B, beta-glucuronidase, and tripeptidyl peptidase 1. A second DBS sample is incubated with a mix of substrate and IS for acetyl-CoA:alpha-glucosaminide N-acetyltransferase; and third DBS sample with a mix of substrate and IS for palmitoyl-protein thioesterase 1. Following overnight incubation, the samples are combined, extracted by liquid-liquid extraction, and analyzed by tandem mass spectrometry.(Unpublished Mayo method)

Day(s) Performed

Thursday

Report Available

8 to 15 days

Specimen Retention Time

1 year

Performing Laboratory

Mayo Clinic Laboratories in Rochester

CPT Code Information

82657

83864 (if appropriate)

LOINC Code Information

Test ID Test Order Name Order LOINC Value
MPS4B MPS IV Panel, BS 104112-8

 

Result ID Test Result Name Result LOINC Value
BG753 Reason for Referral 42349-1
618424 N-acetylgalactosamine-6-sulfatase 88019-5
618425 Beta-galactosidase 55916-1
618426 Interpretation 59462-2
618423 Reviewed By 18771-6