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Test Code MPS3W Mucopolysaccharidosis III, Four-Enzyme Panel, Leukocytes


Shipping Instructions


For optimal isolation of leukocytes, it is recommended the specimen arrive refrigerated within 6 days of collection to be stabilized. Collect specimen Monday through Thursday only and not the day before a holiday. Specimen should be collected and packaged as close to shipping time as possible.



Necessary Information


1. Patient's age is required.

2. Reason for testing is required.



Specimen Required


Container/Tube:

Preferred: Yellow top (ACD solution B)

Acceptable: Yellow top (ACD solution A) or lavender top (EDTA)

Specimen Volume: 6 mL

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


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

618293

Useful For

Supporting the biochemical diagnosis of mucopolysaccharidoses types IIIA, IIIB, IIIC, IIID

 

This test is not useful for carrier detection.

Method Name

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

Specimen Type

Whole Blood ACD

Specimen Minimum Volume

5 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Whole Blood ACD Refrigerated (preferred) 6 days
  Ambient  6 days

Reject Due To

Gross hemolysis Reject

Reference Values

HEPARAN-N-SULFATASE:

>0.13 nmol/hour/mg protein

 

N-ACETYL-ALPHA-D-GLUCOSAMINIDASE:

>0.09 nmol/hour/mg protein

 

HEPARAN-ALPHA-GLUCOSAMINIDE N-ACETYLTRANSFERASE:

>0.24 nmol/hour/mg protein

 

N-ACETYLGLUCOSAMINE-6-SULFATASE:

>0.03 nmol/hour/mg protein

 

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 analysis), and a phone number to reach one of the laboratory directors in case the referring physician has additional questions.

Method Description

Leukocytes are incubated with four cocktail mixes: 1) 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; 2) substrate and IS for acetyl-CoA:alpha-glucosaminide N-acetyltransferase; 3) substrate and IS for N-acetylglucosamine-6-sulfatase; and 4) substrate and IS for palmitoyl-protein thioesterase 1 in 96-well plates. Following overnight incubation, the plates are combined and purified by liquid-liquid extraction. The extracts are evaporated, reconstituted with mobile phase, and analyzed by tandem mass spectrometry.(Unpublished Mayo method)

Day(s) Performed

Preanalytical processing: Monday through Saturday

Testing performed: Tuesday

Report Available

8 to 15 days

Specimen Retention Time

WBC homogenate: 1 month

Performing Laboratory

Mayo Clinic Laboratories in Rochester

CPT Code Information

82657

LOINC Code Information

Test ID Test Order Name Order LOINC Value
MPS3W MPS III (Four) Panel, WBC 104072-4

 

Result ID Test Result Name Result LOINC Value
BG767 Reason for Referral 42349-1
618456 Heparan-N-sulfatase 24086-1
618457 N-acetyl-alpha-D-glucosaminidase 24092-9
618458 Heparan-alpha-glucosaminide N-acetyltransferase 24044-0
618459 N-acetylglucosamine-6-sulfatase 24098-6
618460 Interpretation 59462-2
618455 Reviewed By 18771-6