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HelpTest Code PSY Psychosine, Blood Spot
Reporting Name
Psychosine, BSPerforming Laboratory
Mayo Clinic Laboratories in Rochester
Useful For
Aids in the biochemical detection of Krabbe disease and saposin A cofactor deficiency
Second-tier testing or follow up testing after an abnormal newborn screening result in an infant for Krabbe disease
This test is not capable of identifying carriers of Krabbe disease.
This test is not intended for long-term monitoring of individuals being treated for Krabbe disease or for older children or adult patients at risk to develop Krabbe disease.
Method Name
Liquid Chromatography Tandem Mass Spectrometry (LC-MS/MS)
Ordering Guidance
This test is recommended for newborns or infants who have not had previous psychosine testing. This test is not intended to be used as a monitoring test for individuals with Krabbe disease who are treated or for children or adults at risk of developing Krabbe disease. For patients older than infancy, order PSYR / Psychosine, Whole Blood.
Specimen Required
Supplies: Card-Blood Spot Collection (Filter Paper) (T493)
Container/Tube:
Preferred: Card-Blood Spot Collection (Filter Paper)
Acceptable: PerkinElmer 226 filter paper, Munktell filter paper, Whatman protein Saver 903 paper, local newborn screening card, or blood collected in tubes containing EDTA (preferred) or heparin and dried on filter paper
Specimen Volume: 2 Blood spots
Collection Instructions:
1. Completely fill at least 2 circles on the filter paper card (approximately 100 microliters blood per circle).
2. Let blood dry on filter paper at ambient temperature in a horizontal position for a minimum of 3 hours.
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 Type
Whole bloodSpecimen Minimum Volume
1 Blood spot
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Whole blood | Ambient (preferred) | 96 days | FILTER PAPER |
| Frozen | 96 days | FILTER PAPER | |
| Refrigerated | 96 days | FILTER PAPER |
Reject Due To
| Blood spot specimen that shows serum rings or has multiple layers | Reject |
| Insufficient specimen | Reject |
| Nonapproved filter paper | Reject |
Reference Values
Normal <2 nmol/L
Interpretation
An interpretive report will be provided.
An elevation of psychosine is indicative of symptomatic Krabbe disease or symptomatic saposin A cofactor deficiency.
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.
Day(s) Performed
Monday through Sunday
Report Available
1 to 2 daysTest Classification
This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. It has not been cleared or approved by the US Food and Drug Administration.CPT Code Information
82542
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| PSY | Psychosine, BS | 93688-0 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| 62235 | Psychosine | 93688-0 |
| 36342 | Reviewed By | 18771-6 |
| 36343 | Interpretation (PSY) | 59462-2 |
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.
Special Instructions
- Biochemical Genetics Patient Information
- Blood Spot Collection Card-Spanish Instructions
- Blood Spot Collection Card-Chinese Instructions
- Newborn Screen Follow-up for Krabbe Disease: Galactocerebrosidase
- Newborn Screen Follow-up for Krabbe Disease: Galactocerebrosidase and Psychosine
- Blood Spot Collection Instructions
Testing Algorithm
If the patient has abnormal newborn screening result for Krabbe disease, immediate action should be taken. Refer to the appropriate American College of Medical Genetics and Genomics Newborn Screening ACT Sheet.(1,2)
The following are available:
-Newborn Screen Follow-up for Krabbe Disease: Galactocerebrosidase
-Newborn Screen Follow-up for Krabbe Disease: Galactocerebrosidase and Psychosine