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Test Code MISC2MAYOALLOI Allo-isoleucine, Blood Spot

Important Note

Miscellaneous Test

Reporting Name

Allo-isoleucine, BS

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

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Specimen Type

Whole blood

Specimen Required

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

Container/Tube: Local newborn 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 >1 year of age is fingerstick.

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

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

6. Do not stack wet specimens.

7. Keep specimen dry.

8. Let blood dry on the Blood Spot Collection Card (T493) at ambient temperature in a horizontal position for 3 hours before adding additional blood spots to the card.

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

Blood spot: 1

Specimen Stability Information

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

Reference Values

Allo-isoleucine: <2 nmol/mL

Leucine: 35-215 nmol/mL

Isoleucine: 13-130 nmol/mL

Valine: 51-325 nmol/mL

An interpretive report will also be provided.

Day(s) and Time(s) Performed

Monday through Friday; Varies

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
ALLOI Allo-isoleucine, BS 94571-7


Result ID Test Result Name Result LOINC Value
27446 Specimen 31208-2
27447 Specimen ID 57723-9
27448 Source 31208-2
27449 Order Date 82785-7
27450 Reason For Referral 42349-1
27451 Method 49549-9
27457 Allo-isoleucine 94572-5
27458 Leucine 47679-6
27459 Isoleucine 47671-3
27460 Valine 47799-2
27453 Interpretation 46743-1
27454 Amendment 48767-8
27455 Reviewed By 18771-6
27456 Release Date 82772-5

Reject Due To

All specimens will be evaluated at Mayo Clinic Laboratories for test suitability.

Method Name

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

Portions of this test are covered by patents held by Quest Diagnostics

Secondary ID



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