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Test Code LAB91 Methemoglobin Reductase, Blood

Additional Codes

Mayo Test Code: METR

Reporting Name

Methemoglobin Reductase, B

Useful For

Confirming cases of suspected methemoglobin reductase (cytochrome b5 reductase) deficiency


Functional studies in families with methemoglobin reductase (cytochrome b5 reductase) deficiency

Method Name

Kinetic Spectrophotometry (KS)

Performing Laboratory

Mayo Medical Laboratories in Rochester

Specimen Type

Whole Blood ACD-B

Specimen Required


Preferred: Yellow top (ACD)

Acceptable: Lavender top (EDTA)

Specimen Volume: 6 mL

Collection Instructions: Do not transfer blood to other containers.

Additional Information: Patient's age is required.

Specimen Minimum Volume

1 mL

Specimen Stability Information

Specimen Type Temperature Time
Whole Blood ACD-B Refrigerated 22 days

Reject Due To


Mild OK; Gross reject







Reference Values

≥12 months: 6.6-13.3 U/g Hb

Reference values have not been established for patients who are <12 months of age.

Day(s) and Time(s) Performed

Tuesday, Friday

CPT Code Information


LOINC Code Information

Test ID Test Order Name Order LOINC Value
METR Methemoglobin Reductase, B 32703-1


Result ID Test Result Name Result LOINC Value
9322 Methemoglobin Reductase, B 32703-1

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.