Meth-Hemoglobin Test
Meth-Hemoglobin Test
The methemoglobin test measures the amount of meth-hemoglobin in the blood. Meth-hemoglobin (MetHb) is a form of hemoglobin that reduces the blood's ability to carry oxygen, leading to oxygen deprivation (hypoxia). It is found naturally in the blood in a small quantity (<1%). However, an increase in its levels can result in the development of methemoglobinemia, a rare blood disorder.
Methemoglobinemia can happen when someone inherits a deficiency of the reductase enzyme or has a defect in the hemoglobin structure called hemoglobin M. Exposure to toxic substances like nitrates, nitrites, aniline dyes, and certain topical anesthetic agents such as benzocaine, lidocaine, or prilocaine, can also cause methemoglobinemia and may require immediate treatment.
Doctors may order a methemoglobin test if they suspect methemoglobinemia in a child or adult with unexplained cyanosis and breathing difficulties and want to institute appropriate treatment to prevent potential complications.
What is the Meth-hemoglobin Test Used For?
Meth-Hemoglobin test is done
To diagnose meth-hemoglobinemia in patients with unexplained cyanosis or suspected toxicological effects from chemicals or drugs
To differentiate meth-hemoglobinemia from other causes of cyanosis (e.g. congenital heart disease)
Symptoms of Methemoglobinemia
Symptoms of meth-hemoglobinemia may vary widely based on the levels of this protein in the blood and the underlying health status of the patient. General physical findings may include: Bluish discoloration of the skin and mucous membrane(cyanosis)
Chocolate colored blood
Headache and temporary loss of consciousness
Tiredness, drowsiness, and slow reflex
Pale skin or conjunctiva (suggestive of anemia)
Patients with very high methemoglobin levels can experience
Seizure
Irregular heartbeat
Rapid breathing
Confusion
Preparation for Test
No specific preparation is required to do a Meth-Hemoglobin test. However, ensure that your doctor knows all the medications you are taking or the underlying medical conditions you may have.
Interpretation of Test Results
Meth-Hemoglobin blood concentrations are interpreted along with the patient's medical history and data from other laboratory tests. They are often expressed as percentages (%) or grams per decilitre(g/dL), with reference ranges provided as follows:
|
Fraction of Meth-Hemoglobin (%) |
Interpretation |
|
1 - 2% |
Normal |
|
2 - 10% |
Mild increase indicates methemoglobinemia, usually asymptomatic |
|
10 - 30% |
Moderate increase, some degree of cyanosis seen, need medical attention |
|
30 - 50% |
More severe, cause cyanosis and other symptoms, require immediate treatment |
|
50 -70 % |
Very severe, associated with neurologic and cardiac symptoms |
|
>70 % |
Organ failure and high fatality |
FAQs
When should I get a Meth-Hemoglobin test?
Consider taking a methemoglobin test if you have a family history of methemoglobinemia or experience symptoms of the disorder after possible exposure to a toxic substance or medication.
What is the treatment for meth-hemoglobinemia?
Treatment for meth-hemoglobinemia is generally based on a person's specific symptoms. Initial care often involves providing supplemental oxygen. However, for symptomatic individuals who have high methemoglobin levels, methylene blue is the preferred treatment option (contraindicated in people with Glucose-6-phosphate dehydrogenase deficiency and hemoglobin M). When methylene blue does not work, patients may undergo red blood cell transfusion, hyperbaric oxygen therapy, exchange transfusions, or receive vitamin C.
Can medications affect my meth-hemoglobin results?
Yes, medications such as sulfonamides, lidocaine, benzocaine, chloroquine, sodium valproate, and primaquine can cause an abrupt rise in meth-hemoglobin levels, affecting your test results.
Can this test be performed during pregnancy?
Yes, this test can be performed during pregnancy, but only if the doctor thinks it's necessary
Are there any risks involved in the Meth-Hemoglobin Test?
Because meth-hemoglobin is a blood test, there is a slight possibility that you may have swelling, tenderness, slight pain, or excessive bleeding at the site of needle insertion and, on extremely rare occasions, infection. However, most symptoms go away quickly.
Related tests
Tests At Lupin Diagnostics