Test ID MET Methemoglobin and Sulfhemoglobin, Blood
Reporting Name
Methemoglobin and Sulfhemoglobin, BUseful For
Diagnosing methemoglobinemia and sulfhemoglobinemia
Identifying cyanosis due to other causes, such as congenital heart disease
Profile Information
Test ID | Reporting Name | Available Separately | Always Performed |
---|---|---|---|
METH | Methemoglobin, B | No | Yes |
SULF | Sulfhemoglobin, B | No | Yes |
Specimen Type
Whole Blood EDTASpecimen Required
Specimen must arrive within 72 hours of draw.
Container/Tube: Lavender top (EDTA)
Specimen Volume: Full tube
Additional Information: Patient's age is required.
Specimen Minimum Volume
1 mL
Specimen Stability Information
Specimen Type | Temperature | Time | Special Container |
---|---|---|---|
Whole Blood EDTA | Refrigerated | 72 hours |
Reference Values
METHEMOGLOBIN
0-11 months: not established
≥1 year: 0.0-1.5% of total hemoglobin
SULFHEMOGLOBIN
0-11 months: not established
≥1 year: 0.0-0.4% of total hemoglobin
Day(s) and Time(s) Performed
Monday through Saturday; Continuously
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
83050-Methemoglobin
83060-Sulfhemoglobin
LOINC Code Information
Test ID | Test Order Name | Order LOINC Value |
---|---|---|
MET | Methemoglobin and Sulfhemoglobin, B | In Process |
Result ID | Test Result Name | Result LOINC Value |
---|---|---|
8268 | Methemoglobin, B | 2614-6 |
8272 | Sulfhemoglobin, B | 4685-4 |
Clinical Information
Methemoglobin:
When iron in hemoglobin is oxidized from the normal divalent state to a trivalent state, the resulting brownish pigment is methemoglobin. Methemoglobin cannot combine reversibly with oxygen and is associated with cyanosis.
Methemoglobinemia, with or without sulfhemoglobinemia, is most commonly encountered as a result of administration of medications such as phenacetin, phenazopyridine, sulfonamides, local anesthetics, dapsone, or following ingestion of nitrites or nitrates. Congenital methemoglobinemias are rare. They are either due to:
-Deficiency of methemoglobin reductase (also called cytochrome B5 reductase or diaphorase) in erythrocytes, an autosomal recessive disorder.
-One of several intrinsic structural disorders of hemoglobin, called methemoglobin-M, all of which are inherited in the autosomal dominant mode.
Methemoglobinemia responds to treatment with methylene blue or ascorbic acid.
Sulfhemoglobin:
Sulfhemoglobin cannot combine with oxygen. Sulfhemoglobinemia is associated with cyanosis and often accompanies drug-induced methemoglobinemia. Sulfhemoglobinemia can be due to exposure to trinitrotoluene or zinc ethylene bisdithiocarbamate (a fungicide), or by ingestion of therapeutic doses of flutamide.
In contrast to methemoglobinemia, sulfhemoglobinemia persists until the erythrocytes containing it are destroyed. Therefore, blood level of sulfhemoglobin declines gradually over a period of weeks.
Patients with sulfhemoglobinemia often also have methemoglobinemia. There is no specific treatment for sulfhemoglobinemia. Therapy is directed at reversing the methemoglobinemia, if present.
Interpretation
In congenital methemoglobinemia, the methemoglobinemia concentration in blood is about 15% to 20% of total hemoglobin. Such patients are mildly cyanotic and asymptomatic.
In acquired (toxic) methemoglobinemia, the concentration may be much higher. Symptoms may be severe when methemoglobin is >40% of hemoglobin. Very high concentrations (>70%) may be fatal.
Clinical Reference
Beutler E: Methemoglobinemia and other causes of cyanosis. In Hematology. Sixth edition. Edited by WJ Williams, E Beutler, AJ Erslev, MA Lichtman. New York, McGraw-Hill Book Company, 2001, pp 611-614
Analytic Time
Same day/1 dayMethod Name
Spectrophotometry (SP)
Forms
If not ordering electronically, complete, print, and send a Benign Hematology Test Request Form (T755) with the specimen.