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Test Code HCMM Homocysteine (Total), Methylmalonic Acid, and Methylcitric Acid, Blood Spot


Ordering Guidance


The preferred test for evaluating adults for an inherited disorder of methionine, cobalamin, or propionate metabolism is CMMPP / Cobalamin, Methionine, and Methylmalonic Acid Pathways, Plasma or CMMPS / Cobalamin, Methionine, and Methylmalonic Acid Pathways, Serum.



Specimen Required


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

Container/Tube:

Preferred: Card-Blood Spot Collection (Filter Paper)

Acceptable: Local newborn screening card, Whatman Protein Saver 903 filter paper, PerkinElmer 226 (formerly Ahlstrom 226) filter paper, Munktell filter paper

Specimen Volume: 2 Blood spots

Collection Instructions:

1. Do not use device or capillary tube containing EDTA or ACD to collect specimen. Sodium heparin is acceptable but must be spotted on card the same day as collected.

2. Completely fill at least 2 circles on the filter paper card (approximately 100 microliters blood per circle) using blood from a heel or finger stick.

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

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

5. Do not stack wet specimens.

6. 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)


Useful For

Second-tier assay of newborn screening specimens when abnormal propionyl carnitine or methionine concentrations are identified in a primary newborn screen

Method Name

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

Reporting Name

HCMM, BS

Specimen Type

Whole blood

Specimen Minimum Volume

1 Blood spot

Specimen Stability Information

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

Reference Values

HOMOCYSTEINE:

<9.0 nmol/mL

 

METHYLMALONIC ACID:

<4.0 nmol/mL

 

METHYLCITRIC ACID:

<1.0 nmol/mL

 

An interpretive report will also be provided.

Day(s) Performed

Monday, Thursday

Report Available

3 to 6 days

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. It has not been cleared or approved by the US Food and Drug Administration.

CPT Code Information

83090

83918

LOINC Code Information

Test ID Test Order Name Order LOINC Value
HCMM HCMM, BS 100765-7

 

Result ID Test Result Name Result LOINC Value
50252 Homocysteine 54301-7
50253 Methylmalonic Acid 82385-6
50254 Methylcitric Acid 82386-4
50255 Interpretation 59462-2
50257 Reviewed By 18771-6