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Test Code PSY Psychosine, Blood Spot

Useful For

Aids in the biochemical diagnosis of Krabbe disease and saposin A cofactor deficiency


Follow-up of individuals affected with Krabbe disease


Follow-up testing after an abnormal newborn screening result for Krabbe disease


This test is not capable of identifying carriers of Krabbe disease.

Reporting Name

Psychosine, BS

Specimen Type

Whole blood

Advisory Information

This test is recommended for newborns or infants who have not had previous psychosine testing.


If requesting psychosine testing for either diagnostic or monitoring purposes, order PSYR / Psychosine, Whole Blood.

Shipping Instructions


Specimen Required

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


Preferred: Card-Blood Spot Collection (Filter Paper)

Acceptable: Ahlstrom 226 filter paper, Munktell filter paper, Whatman protein Saver 903 paper, or blood collected in tubes containing heparin or EDTA 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 3 or more 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 in Special Instructions.

2. For collection instructions in Spanish, see Blood Spot Collection Card-Spanish Instructions (T777) in Special Instructions.

3. For collection instructions in Chinese, see Blood Spot Collection Card-Chinese Instructions (T800) in Special Instructions.

Specimen 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

Reference Values

Normal <2 nmol/L psychosine

Day(s) and Time(s) Performed

Monday through Sunday; 7 a.m.

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Test Classification

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 U.S. Food and Drug Administration.

CPT Code Information


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

Method Name

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


1. Biochemical Genetics Patient Information (T602) in Special Instructions.

2. If not ordering electronically, complete, print, and send an Inborn Errors of Metabolism Test Request (T798) with the specimen.