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Order Code GPSY Glucopsychosine, Blood Spot

Useful For

Second-tier test when newborn screening results with reduced beta-glucosidase (GBA) activity are identified

 

Diagnosis and monitoring of patients with Gaucher disease using dried blood spot specimens

 

Monitoring a patient's response to treatment

 

This test is not useful for identifying carriers of GBA variants.

Reporting Name

Glucopsychosine, BS

Specimen Type

Whole blood


Ordering Guidance


This test is also available as a part of a panel; see HSMBS / Hepatosplenomegaly Panel, Blood Spot. If this test (GPSY) is ordered with either CTXBS / Cerebrotendinous Xanthomatosis, Blood Spot or OXYBS / Oxysterols, Blood Spot, the individual tests will be canceled and HSMBS ordered.



Specimen Required


Supplies:

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

-Card-Postmortem Screening (Filter Paper) (T525)

Collection Container/Tube:

Preferred: Blood Spot Collection (Filter Paper)

Acceptable: Whatman Protein Saver 903 filter paper, PerkinElmer 226 filter paper, Munktell filter paper, Postmortem Screening card, or collected with sodium heparin, lithium heparin, ACD-B or EDTA containing devices

Specimen Volume: 2 Blood spots

Collection Instructions:

1. Let blood dry completely on filter paper at ambient temperature in a horizontal position for a minimum of 3 hours.

2. At least 1 spot should be complete, (ie, unpunched)

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

4. Do not stack wet specimens.

5. 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 Minimum Volume

1 Blood spot

Specimen Stability Information

Specimen Type Temperature Time Special Container
Whole blood Refrigerated (preferred) 10 days FILTER PAPER
  Frozen  59 days FILTER PAPER
  Ambient  10 days FILTER PAPER

Reject Due To

Blood spot showing serum rings
Insufficient specimen
Layering
Multiple applications		 Reject

Reference Values

Cutoff: ≤0.040 nmol/mL

Method Description

A 3-mm dried blood spot is extracted with internal standard. The extract is subjected to liquid chromatography tandem mass spectrometry (LC-MS/MS) analysis. The MS/MS is operated in the multiple reaction monitoring positive mode to follow the precursor to product species transitions for each analyte and internal standard. The ratio of the extracted peak areas to internal standard determined by the LC-MS/MS is used to calculate the concentration of in the sample.(Unpublished Mayo method)

Day(s) Performed

Tuesday

Performing Laboratory

Mayo Clinic Laboratories in Rochester

CPT Code Information

82542

Method Name

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

Forms

1. Biochemical Genetics Patient Information (T602)

2. If not ordering electronically, complete, print, and send a Biochemical Genetics Test Request (T798) with the specimen.

Testing Algorithm

For more information see Newborn Screen Follow-up for Gaucher Disease

 

If the patient has abnormal newborn screening results for Gaucher disease, refer to the appropriate American College of Medical Genetics and Genomics Newborn Screening ACT Sheet.(1)

Genetics Test Information

Gaucher disease is an autosomal recessive lysosomal storage disorder caused by deficient beta-glucosidase activity.

 

There are 3 described types of Gaucher disease with varying clinical presentations generally distinguished based on whether there is central nervous system involvement.

 

Glucopsychosine (glucosylsphingosine: lyso-GL1) is elevated in symptomatic patients and supports a diagnosis of Gaucher disease.