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Order Code KD2T Krabbe Disease Second-Tier Newborn Screen, Blood Spot


Necessary Information


1. Birth weight (grams)

2. Time of birth (24-hour time)

3. Gestational age (weeks)



Specimen Required


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

Container/Tube:

Preferred: Blood Spot Collection Card

Acceptable: PerkinElmer 226 filter paper, Munktell filter paper, Whatman Protein Saver 903 paper, local newborn screening card, or blood collected in tubes containing heparin or EDTA and dried on filter paper.

Specimen Volume: 3 Blood spots

Collection Instructions:

1. Completely fill at least 3 circles on the filter paper card (approximated 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).


Forms

1. New York Clients-Informed consent is required. Document on the request form or electronic order that a copy is on file. The following documents are available:

-Informed Consent for Genetic Testing (T576)

-Informed Consent for Genetic Testing-Spanish (T826)

2. Biochemical Genetics Patient Information (T602).

Useful For

Second-tier testing of newborns with an abnormal screening result for Krabbe disease

 

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

Genetics Test Information

This test is used as a second-tier newborn screen for Krabbe disease (galactocerebrosidase deficiency) and includes both psychosine measurement and DNA analysis for the 30-kb deletion.

Method Name

Liquid Chromatography Tandem Mass Spectrometry (LC-MS/MS)/Polymerase Chain Reaction with Gel Electrophoresis

Reporting Name

Krabbe Disease 2ND Tier NBS, BS

Specimen Type

Whole blood

Specimen Minimum Volume

2 Blood spots

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/applications Reject
Insufficient specimen Reject

Reference Values

An interpretive report will be provided.

Method Description

Protocol 1:

Internal standard is added to a dried blood spot. The extract is evaporated and reconstituted prior to injection onto a liquid chromatography tandem mass spectrometry (LC-MS/MS). Following separation of the structural isomers glucopsychosine and psychosine by liquid chromatography, their concentrations are measured by MS/MS analysis in the multiple reaction monitoring positive mode to follow the precursor to product species transitions for psychosine (PSY). The ratio of the extracted peak area of PSY to internal standard as determined by LC-MS/MS is used to calculate the concentration of PSY in the sample.(Unpublished Mayo method)

 

Protocol 2:

A polymerase chain reaction-based assay is used to examine DNA for the presence of a 30-kilobase deletion encompassing exon 11 through the end of the GALC gene.(Unpublished Mayo method)

Day(s) Performed

Monday through Saturday

Performing Laboratory

Mayo Clinic Laboratories in Rochester

CPT Code Information

82542

81401

Testing Algorithm

If the patient has abnormal newborn screening result for Krabbe disease, immediate action should be taken. Refer to the appropriate ACMG Newborn Screening ACT Sheet.(1)