Methemoglobinemia Evaluation, Blood
Use
The Methemoglobinemia Evaluation test is used for diagnosing methemoglobinemia and sulfhemoglobinemia and assessing possible hereditary causes. This test is useful for differentiating these conditions from other cyanotic disorders, such as congenital heart disease. Methemoglobin forms when the hemoglobin molecule iron is in the ferric form instead of the functional ferrous form, leading to the condition methemoglobinemia with levels greater than normal. The test results provide information essential for managing these disorders, particularly for identifying hereditary causes like deficiencies in cytochrome b5 reductase or structure anomalies in hemoglobin, known as M-Hbs.
Special Instructions
Specimen must arrive within 72 hours of collection. Include recent transfusion details and a complete blood count. Metabolic Hematology Patient Information form is recommended for optimal evaluation. The laboratory can provide molecular testing when needed, based on adequate sample volume.
Limitations
Methemoglobin is unstable, degrading by about 40% every 24 hours, thus stored or shipped specimens might yield a normal value that doesn't exclude prior methemoglobinemia. Some hemoglobin variants may interfere with sulfhemoglobin absorbance tests, emphasizing the importance of methods like HPLC for accurate results.
New York Approved
Methodology
Other
Biomarkers
LOINC Codes
- 2614-6
- 4685-4
- 20572-4
- 32682-7
- 4552-6
- 24469-9
- 78748-1
- 32703-1
- 59465-5
- 18771-6
Result Turnaround Time
3-25 days
Related Documents
For more information, please review the documents below
Specimen
Whole Blood
Volume
4 mL each for EDTA; 6 mL for ACD
Minimum Volume
3 mL for EDTA; 2.7 mL for ACD
Container
Lavender top (EDTA) and yellow top (ACD solution B)
Collection Instructions
Send whole blood specimen in original tube. Do not aliquot.
Storage Instructions
Refrigerated
Causes for Rejection
Gross hemolysis
Stability Requirements
| Temperature | Period |
|---|---|
| Refrigerated | 72 hours |