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HelpTest Code METR1 Cytochrome b5 Reductase Enzyme Activity, Blood
Necessary Information
Specimen Required
Collection Container/Tube:
Preferred: Yellow top (ACD)
Acceptable: Lavender top (EDTA)
Specimen Volume: 6 mL
Collection Instructions: Send whole blood specimen in original tube. Do not aliquot.
Useful For
Evaluation of patients with cyanosis
Confirming cases of suspected cytochrome b5 reductase (methemoglobin reductase) deficiency
Functional studies in families with cytochrome b5 reductase deficiency
Reporting Name
Cytochrome b5 Reductase, BSpecimen Type
Whole Blood ACD-BSpecimen Minimum Volume
1 mL
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Whole Blood ACD-B | Refrigerated | 18 days |
Reject Due To
| Gross hemolysis | Reject |
Reference Values
≥12 months of age: 7.8-13.1 U/g Hb
Reference values have not been established for patients who are younger than 12 months.
Specimen Retention Time
7 daysPerforming Laboratory
Mayo Clinic Laboratories in Rochester
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| METR1 | Cytochrome b5 Reductase, B | 32703-1 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| METRB | Cytochrome b5 Reductase, B | 32703-1 |
Day(s) Performed
Performed weekly
Report Available
1 to 6 daysCPT Code Information
82657
Forms
If not ordering electronically, complete, print, and send a Benign Hematology Test Request (T755) with the specimen