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Test Code ALLOI Allo-isoleucine, Blood Spot

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Reporting Name

Allo-isoleucine, BS

Specimen Type

Whole blood


Specimen Required


Supplies:

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

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

Container/Tube:

Preferred: Blood Spot Collection (Filter Paper)

Acceptable: Local newborn screening card, Whatman Protein Saver 903 filter paper, PerkinElmer 226 filter paper, Munktell filter paper, Postmortem Screening Card

Specimen Volume: 2 Blood spots

Collection Instructions:

1. Do not use device or capillary tube containing EDTA to collect specimen.

2. At least 1 spot should be complete and unpunched.

3. An alternative blood collection option for a patient older than 1 year is a fingerstick. For detailed instructions, see How to Collect a Dried Blood Spot Sample.

4. Include type of feeding information on the collection card.

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

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

7. Do not stack wet specimens.

8. 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).


Reject Due To

Blood spot specimen that shows layering Reject
Blood spot specimen that shows serum rings Reject
Blood spot specimen that shows multiple applications Reject
Blood spot specimen that shows insufficient specimen Reject

Specimen Stability Information

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

Specimen Minimum Volume

1 Blood spot

Day(s) Performed

Monday through Friday

Specimen Retention Time

1 year

Report Available

2 to 4 days

Reference Values

Allo-isoleucine: <4 nmol/mL

Leucine: 52-269 nmol/mL

Isoleucine: 22-167 nmol/mL

Valine: 84-414 nmol/mL

 

An interpretive report will also be provided.

Useful For

Evaluation of newborn screening specimens that test positive for branched-chain amino acids elevations

 

Follow-up of patients with maple syrup urine disease

CPT Code Information

82136

LOINC Code Information

Test ID Test Order Name Order LOINC Value
ALLOI Allo-isoleucine, BS 94571-7

 

Result ID Test Result Name Result LOINC Value
27453 Interpretation 46743-1
27457 Allo-isoleucine 94572-5
27458 Leucine 47679-6
27459 Isoleucine 47671-3
27460 Valine 47799-2
27455 Reviewed By 18771-6

Genetics Test Information

Second-tier test for abnormal newborn screen and follow-up of patients with maple syrup urine disease.

Supportive Data

In a blinded study containing specimens obtained from maple syrup urine disease (MSUD) cases (n=16), non-MSUD patients treated with total parenteral nutrition (n=19), and healthy controls (n=541), this assay correctly identified all MSUD and non-MSUD cases.