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Test Code MPS1R Endogenous Mucopolysaccharidosis Type I (IDUA [Alpha-L-Iduronidase]) Biomarker Reflex, Blood Spot


Ordering Guidance


This test is recommended for assessment of newborns and infants with a positive newborn screen (reduced IDUA activity) for mucopolysaccharidosis type I (MPS I). This test is not intended to be used as a monitoring test for individuals with confirmed MPS I.



Shipping Instructions


Specimens stored at ambient temperatures for more than 13 days after collection may result in false-positive results in carrier and other unaffected individuals.



Specimen Required


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, local newborn screening card, postmortem screening card, 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. Completely fill at least 2 circles on filter paper card (approximately 100 microliters blood per circle).

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)


Secondary ID

622360

Useful For

Second-tier testing of newborns with an abnormal primary screening result for mucopolysaccharidosis type I (MPS I, decreased alpha-L-iduronidase activity) where quantitation of the glycosaminoglycans dermatan and heparan sulfate is desired in the presence of elevated endogenous MPS I biomarkers

 

Follow-up testing for evaluation of an abnormal newborn screening result for MPS I

 

This test is not useful a monitoring test for individuals with MPS I.

 

This test is not appropriate for carrier detection.

Reflex Tests

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

Testing Algorithm

Testing begins with analysis of the mucopolysaccharidosis type I (MPS I) specific endogenous biomarker. If it is within the normal range, testing is complete. If the MPS I specific endogenous biomarker is elevated, quantification of heparan sulfate, dermatan sulfate, and keratan sulfate will be performed at an additional charge.

 

If the patient has abnormal newborn screening results for MPS I, timely action should be taken. Refer to the appropriate American College of Medical Genetics and Genomics Newborn Screening ACT Sheet.(1)

 

For more information see Newborn Screen Follow-up for Mucopolysaccharidosis Type I.

Method Name

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

Specimen Type

Whole blood

Specimen Minimum Volume

1 Blood spot

Specimen Stability Information

Specimen Type Temperature Time Special Container
Whole blood Refrigerated (preferred) 30 days FILTER PAPER
  Frozen  90 days FILTER PAPER
  Ambient  13 days FILTER PAPER

Reject Due To

Blood spot specimen that shows serum rings or has multiple layers/applications Reject

Reference Values

An interpretive report will be provided.

Interpretation

The measurements of mucopolysaccharidosis type I (MPS I) specific endogenous biomarker is compared to the reference value. This report is in text form only, indicating if the MPS I specific endogenous biomarker value is or is not suggestive of a biochemical diagnosis of MPS I. In any specimen where the MPS I specific endogenous biomarker value is elevated, quantitative analysis of heparan, dermatan, and keratan sulfate will be performed. Abnormal results are not sufficient to conclusively establish a diagnosis of a particular disease. To verify a preliminary diagnosis, independent biochemical (ie, in vitro enzyme assay and quantitative glycosaminoglycan measurement) or molecular genetic analyses are required, many of which are offered within Mayo Clinic Laboratories. Recommendations for additional biochemical testing and confirmatory studies (biomarker, enzyme assay, molecular analysis) are provided in the interpretative report.

Method Description

Sample preparation consists of extraction from dried blood spots using aqueous buffer and the addition of reagents to aid in removing the analytes from the filter paper. The resulting extracted analytes are chemically derived to aid in chromatographic separation and to increase signal intensity. A liquid/liquid extraction is preformed to remove the derived analytes from bulk matrix. The sample is then analyzed via liquid chromatography tandem mass spectrometry.(Unpublished Mayo method)

Day(s) Performed

Monday, Thursday

Report Available

3 to 6 days

Specimen Retention Time

6 months

Performing Laboratory

Mayo Clinic Laboratories in Rochester

CPT Code Information

82542

LOINC Code Information

Test ID Test Order Name Order LOINC Value
MPS1R MPS I Biomarker Reflex, BS In Process

 

Result ID Test Result Name Result LOINC Value
622361 Interpretation 59462-2
622362 Reviewed by 18771-6