| Web: | mayocliniclabs.com |
|---|---|
| Email: | mcl@mayo.edu |
| Telephone: | 800-533-1710 |
| International: | +1 855-379-3115 |
| Values are valid only on day of printing | |
Test Id : PSYR
Psychosine, Whole Blood
Useful For
Suggests clinical disorders or settings where the test may be helpful
Suggests clinical disorders or settings where the test may be helpful
Aiding in the biochemical diagnosis of Krabbe disease using whole blood specimens
Follow-up of individuals affected with Krabbe disease
Follow-up testing after an abnormal newborn screening result for Krabbe disease
Monitoring of individuals at risk to develop late onset Krabbe disease
Monitoring of individuals with Krabbe disease after hematopoietic stem cell transplantation
Genetics Test Information
Provides information that may help with selection of the correct genetic test or proper submission of the test request
Provides information that may help with selection of the correct genetic test or proper submission of the test request
Krabbe disease (globoid cell leukodystrophy) is an autosomal recessive lysosomal disorder caused by deficient activity of the enzyme galactocerebrosidase (GALC).
Krabbe disease is clinically variable and infantile-onset Krabbe disease is the most severe variant with rapid neurological regression resulting in early death.
Elevations in psychosine support a diagnosis of Krabbe disease; therefore, psychosine quantitation is a useful biomarker in determining if an individual has active disease. In addition, psychosine may be a valuable biomarker to monitor disease progression, or treatment response.
Psychosine may also be elevated in saposin A cofactor deficiency, which results in a similar clinical phenotype to Krabbe disease, but patients typically have normal GALC activity in vitro.
Method Name
A short description of the method used to perform the test
A short description of the method used to perform the test
Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS)
NY State Available
Indicates the status of NY State approval and if the test is orderable for NY State clients.
Indicates the status of NY State approval and if the test is orderable for NY State clients.
Yes
Reporting Name
Lists a shorter or abbreviated version of the Published Name for a test
Lists a shorter or abbreviated version of the Published Name for a test
Psychosine, RBC
Aliases
Lists additional common names for a test, as an aid in searching
Lists additional common names for a test, as an aid in searching
Galactopsychosine
Galactosylphingosine
Krabbe disease
Psychosine
Specimen Type
Describes the specimen type validated for testing
Describes the specimen type validated for testing
Whole blood
Shipping Instructions
Must be sent refrigerated.
Necessary Information
1. Patient’s age is required.
2. Date of hematopoietic stem cell transplantation (HSCT), if performed.
Specimen Required
Defines the optimal specimen required to perform the test and the preferred volume to complete testing
Defines the optimal specimen required to perform the test and the preferred volume to complete testing
Collection Container/Tube:
Preferred: Lavender top (EDTA)
Acceptable: Green top (sodium heparin, lithium heparin)or yellow top (ACD)
Specimen Volume: 2 mL
Forms
If not ordering electronically, complete, print, and send a Biochemical Genetics Test Request (T798) with the specimen.
Specimen Minimum Volume
Defines the amount of sample necessary to provide a clinically relevant result as determined by the Testing Laboratory
Defines the amount of sample necessary to provide a clinically relevant result as determined by the Testing Laboratory
0.5 mL
Reject Due To
Identifies specimen types and conditions that may cause the specimen to be rejected
Identifies specimen types and conditions that may cause the specimen to be rejected
All specimens will be evaluated at Mayo Clinic Laboratories for test suitability.
Specimen Stability Information
Provides a description of the temperatures required to transport a specimen to the performing laboratory, alternate acceptable temperatures are also included
Provides a description of the temperatures required to transport a specimen to the performing laboratory, alternate acceptable temperatures are also included
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Whole blood | Refrigerated (preferred) | 7 days |
Useful For
Suggests clinical disorders or settings where the test may be helpful
Suggests clinical disorders or settings where the test may be helpful
Aiding in the biochemical diagnosis of Krabbe disease using whole blood specimens
Follow-up of individuals affected with Krabbe disease
Follow-up testing after an abnormal newborn screening result for Krabbe disease
Monitoring of individuals at risk to develop late onset Krabbe disease
Monitoring of individuals with Krabbe disease after hematopoietic stem cell transplantation
Genetics Test Information
Provides information that may help with selection of the correct genetic test or proper submission of the test request
Provides information that may help with selection of the correct genetic test or proper submission of the test request
Krabbe disease (globoid cell leukodystrophy) is an autosomal recessive lysosomal disorder caused by deficient activity of the enzyme galactocerebrosidase (GALC).
Krabbe disease is clinically variable and infantile-onset Krabbe disease is the most severe variant with rapid neurological regression resulting in early death.
Elevations in psychosine support a diagnosis of Krabbe disease; therefore, psychosine quantitation is a useful biomarker in determining if an individual has active disease. In addition, psychosine may be a valuable biomarker to monitor disease progression, or treatment response.
Psychosine may also be elevated in saposin A cofactor deficiency, which results in a similar clinical phenotype to Krabbe disease, but patients typically have normal GALC activity in vitro.
Clinical Information
Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test
Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test
Krabbe disease (globoid cell leukodystrophy) is an autosomal recessive lysosomal disorder caused by deficient activity of the enzyme galactocerebrosidase (GALC). GALC facilitates the lysosomal degradation of psychosine (galactosylsphingosine) and 3 other substrates (galactosylceramide, lactosylceramide, and lactosylsphingosine). Krabbe disease is caused by alterations in the GALC gene, and it has an estimated frequency of 1 in 250,000 births.
Eighty-five percent to 90% of patients present before the first year of life with central nervous system impairment including increasing irritability, developmental delay, and sensitivity to stimuli. Rapid neurodegeneration including white matter disease follows, with death usually occurring by 2 years of age. Ten percent to 15% of individuals have later onset variants of the disease that are characterized by ataxia, vision loss, weakness, and psychomotor regression, presenting anytime from 6 months to the seventh decade of life. The clinical course of Krabbe disease can be variable, even within the same family.
Newborn screening for Krabbe disease has been implemented in some states. The early (presymptomatic) identification and subsequent testing of infants at risk for Krabbe disease may be helpful in reducing the morbidity and mortality associated with this disease. While treatment is mostly supportive, hematopoietic stem cell transplantation has shown some success if performed prior to onset of neurologic damage.
Psychosine (PSY) is a neurotoxin at elevated concentrations. Importantly, it is 1 of 4 substrates degraded by GALC. It has been shown to be elevated in patients with active Krabbe disease or with saposin A cofactor deficiency, and therefore, may be a useful biomarker for the presence of disease or disease progression.
Reduced or absent GALC in leukocytes (GALCW / Galactocerebrosidase, Leukocytes) or dried blood spots (PLSD / Lysosomal and Peroxisomal Storage Disorders Screen, Blood Spot) along with psychosine analysis can indicate a diagnosis of Krabbe disease. Molecular sequencing of the GALC gene (KRABZ / Krabbe Disease, Full Gene Analysis and Large [30 kb] Deletion, PCR, Varies) allows for detection of the disease-causing alterations in affected patients and carrier detection in family members.
Individuals with a disease phenotype similar to Krabbe disease may have saposin A cofactor deficiency. Saposin A cofactor deficiency also results in elevated psychosine levels. Testing for this condition via molecular analysis of PSAP is useful in those with elevated psychosine and normal to moderately reduced GALC activity with normal molecular genetic GALC analysis.
Reference Values
Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.
Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.
Normal <10 pmol/g Hb
Interpretation
Provides information to assist in interpretation of the test results
Provides information to assist in interpretation of the test results
An elevation of psychosine is indicative of Krabbe disease or saposin A cofactor deficiency.
Cautions
Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances
Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances
No significant cautionary statements
Clinical Reference
Recommendations for in-depth reading of a clinical nature
Recommendations for in-depth reading of a clinical nature
1. Kwon JM, Matern D, Kurtzberg J, et al: Consensus guidelines for newborn screening, diagnosis and treatment of infantile Krabbe disease. Orphanet J Rare Dis. 2018;13(1):30. doi: 10.1186/s13023-018-0766-x
2. Orsini JJ, Escolar ML, Wasserstein MP, et al: Krabbe disease. In Adam MP, Ardinger HH, Pagon RA, et al, eds. GeneReviews [Internet]. University of Washington, Seattle; 2000. Updated October 11, 2018.. Accessed May 2019. Available at: www.ncbi.nlm.nih.gov/books/NBK1238/
3. Turgeon CT, Orsini JJ, Sanders KA, et al: Measurement of psychosine in dried blood spots - a possible improvement to newborn screening programs for Krabbe disease. J Inherit Metab Dis. 2015;38:923-929
4. Wenger DA, Escolar ML, Luzi P, Rafi MA: Krabbe disease (globoid cell leukodystrophy). In: Valle D, Beaudet AL, Vogelstein LB, et al, eds. The Online Metabolic and Molecular Bases of Inherited Disease. McGraw-Hill; 2014 Accessed March 20, 2019. Available at: http://ommbid.mhmedical.com/content.aspx?bookid=971§ionid=62644214
Method Description
Describes how the test is performed and provides a method-specific reference
Describes how the test is performed and provides a method-specific reference
Psychosine is extracted from washed red blood cells and quantified using an isotopically labeled internal standard by LC-MS/MS.(Unpublished Mayo method)
PDF Report
Indicates whether the report includes an additional document with charts, images or other enriched information
Indicates whether the report includes an additional document with charts, images or other enriched information
No
Day(s) Performed
Outlines the days the test is performed. This field reflects the day that the sample must be in the testing laboratory to begin the testing process and includes any specimen preparation and processing time before the test is performed. Some tests are listed as continuously performed, which means that assays are performed multiple times during the day.
Outlines the days the test is performed. This field reflects the day that the sample must be in the testing laboratory to begin the testing process and includes any specimen preparation and processing time before the test is performed. Some tests are listed as continuously performed, which means that assays are performed multiple times during the day.
Tuesday, Thursday
Report Available
The interval of time (receipt of sample at Mayo Clinic Laboratories to results available) taking into account standard setup days and weekends. The first day is the time that it typically takes for a result to be available. The last day is the time it might take, accounting for any necessary repeated testing.
The interval of time (receipt of sample at Mayo Clinic Laboratories to results available) taking into account standard setup days and weekends. The first day is the time that it typically takes for a result to be available. The last day is the time it might take, accounting for any necessary repeated testing.
3 to 7 days
Specimen Retention Time
Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded
Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded
1 year
Performing Laboratory Location
Indicates the location of the laboratory that performs the test
Indicates the location of the laboratory that performs the test
Rochester
Fees
Several factors determine the fee charged to perform a test. Contact your U.S. or International Regional Manager for information about establishing a fee schedule or to learn more about resources to optimize test selection.
Several factors determine the fee charged to perform a test. Contact your U.S. or International Regional Manager for information about establishing a fee schedule or to learn more about resources to optimize test selection.
- Authorized users can sign in to Test Prices for detailed fee information.
- Clients without access to Test Prices can contact Customer Service 24 hours a day, seven days a week.
- Prospective clients should contact their Regional Manager. For assistance, contact Customer Service.
Test Classification
Provides information regarding the medical device classification for laboratory test kits and reagents. Tests may be classified as cleared or approved by the US Food and Drug Administration (FDA) and used per manufacturer instructions, or as products that do not undergo full FDA review and approval, and are then labeled as an Analyte Specific Reagent (ASR) product.
Provides information regarding the medical device classification for laboratory test kits and reagents. Tests may be classified as cleared or approved by the US Food and Drug Administration (FDA) and used per manufacturer instructions, or as products that do not undergo full FDA review and approval, and are then labeled as an Analyte Specific Reagent (ASR) product.
This test was developed, and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the US Food and Drug Administration.
CPT Code Information
Provides guidance in determining the appropriate Current Procedural Terminology (CPT) code(s) information for each test or profile. The listed CPT codes reflect Mayo Clinic Laboratories interpretation of CPT coding requirements. It is the responsibility of each laboratory to determine correct CPT codes to use for billing.
CPT codes are provided by the performing laboratory.
Provides guidance in determining the appropriate Current Procedural Terminology (CPT) code(s) information for each test or profile. The listed CPT codes reflect Mayo Clinic Laboratories interpretation of CPT coding requirements. It is the responsibility of each laboratory to determine correct CPT codes to use for billing.
CPT codes are provided by the performing laboratory.
CPT codes are provided by the performing laboratory.
82542
LOINC® Information
| Test Id | Test Order Name | Order LOINC Value |
|---|---|---|
| PSYR | Psychosine, RBC | 93687-2 |
| Result Id | Test Result Name |
Result LOINC Value
Result LOINC Value Tooltip
|
|---|---|---|
| 606152 | Interpretation (PSYR) | 59462-2 |
| 606145 | Psychosine, RBC | 93687-2 |
| 606151 | Reviewed By | 18771-6 |
Test Setup Resources
Setup Files
Test setup information contains test file definition details to support order and result interfacing between Mayo Clinic Laboratories and your Laboratory Information System.
Test setup information contains test file definition details to support order and result interfacing between Mayo Clinic Laboratories and your Laboratory Information System.
Sample Reports
Normal and Abnormal sample reports are provided as references for report appearance.
Normal and Abnormal sample reports are provided as references for report appearance.
SI Sample Reports
International System (SI) of Unit reports are provided for a limited number of tests. These reports are intended for international account use and are only available through MayoLINK accounts that have been defined to receive them.
International System (SI) of Unit reports are provided for a limited number of tests. These reports are intended for international account use and are only available through MayoLINK accounts that have been defined to receive them.