About the Test
The purpose of a mean corpuscular hemoglobin (MCH) test is to calculate the amount of hemoglobin in an individual red blood cell. The MCH test is one of several tests that are used to diagnose and classify different types of anemia. Anemia is a condition in which there are too few healthy red blood cells, which affects the blood’s ability to carry enough oxygen to organs and tissues in the body.
The MCH test is one of the red blood cell (RBC) indices, a group of tests that is used to characterize the size, shape, and quality of your red blood cells. The RBC indices can be found on a complete blood count report and include:
- Mean corpuscular hemoglobin (MCH)
- Mean corpuscular volume (MCV)
- Mean corpuscular hemoglobin concentration (MCHC)
- Red blood cell distribution width (RDW)
The results of the RBC indices are compared with each other and other blood tests in order to diagnose the cause of anemia.
What does the test measure?
The mean corpuscular hemoglobin test measures the amount of hemoglobin in an individual red blood cell. Hemoglobin is a protein that delivers oxygen from the lungs to organs and tissues and transports carbon dioxide back to the lungs where it can be exhaled. This process is vital for supporting overall health and bodily functions.
When should I get an MCH test?
A mean corpuscular hemoglobin test is part of a complete blood count, a common blood test that is used to diagnose and monitor a wide variety of health conditions. You may have a CBC performed during a routine health examination or if you are being evaluated for a health problem.
Anemia is a common health problem that can be caused by a number of different conditions. If you have signs or symptoms of anemia, your doctor will order a CBC and carefully compare MCH to the other red blood cell indices in order to confirm the diagnosis and help determine the cause.
Initial signs and symptoms of anemia may include:
- Feeling weak or tired more often than usual
- Headaches
- Problems concentrating or thinking
- Feeling irritable
- Loss of appetite
- Numbness and tingling in the hands and feet
Later signs and symptoms of anemia may include:
- Blue color to the whites of the eyes
- Nails that break easily
- Desire to eat ice or other non-food things like dirt
- Dizziness or lightheadedness when you stand up
- Pale skin color
- Shortness of breath with mild activity or even at rest
- Sore or unusually red tongue
- Ulcers in the mouth
- Abnormal or increased menstrual bleeding
Finding an MCH Test
How can I get an MCH test?
An MCH test is included in a complete blood count. Because a full blood draw is generally required for the CBC, this test is most often conducted by a licensed professional in a healthcare setting as part of a routine visit or performed in a laboratory.
If you are concerned about your health and feel an MCH test would be useful, contact your health care provider.
Can I take the test at home?
Options for at-home complete blood count testing, which includes MCH, are available. At-home test kits include tools and instructions for collecting a blood sample, which you can then mail to a laboratory. After lab technicians analyze your blood sample, your results are shared with you through an online health portal or by email. Results usually take 2 to 3 days after the sample is received.
At-home CBC test results are not interpreted by a medical professional. You must share your at-home results with your health care provider who can provide an assessment of your overall health and explain what the results mean. Your doctor may request repeating the CBC test using a traditional blood draw in order to confirm your at-home test results.
How much does the test cost?
The cost of a complete blood count includes MCH and can depend upon a number of factors, namely whether or not you have health insurance. Additionally, there may be out-of-pocket costs such as copays and deductibles.
Your doctor or insurance provider can provide information on expected costs for a complete blood count.
Taking an MCH Test
The MCH test, performed as part of the CBC, requires a blood sample, which is generally ordered and collected by a licensed health care professional. A blood sample is drawn from a vein into a sample tube, usually from the inside crook of your elbow.
Before the test
Unless specified by your provider, there is no special preparation required before collecting a sample for a CBC in order to find the MCH.
A CBC may be ordered at the same time as other blood tests. When you are getting more than one blood test, your provider may give you special instructions for avoiding food for a certain amount of time before the blood draw.
During the test
There are several steps that occur during a blood draw for a CBC test that you can expect:
- A health care provider will identify a vein in your arm, hand, or another part of your body.
- An antiseptic alcohol wipe is used to cleanse the area that the needle will be inserted. This is most often either inside the elbow or at the top of the hand.
- To make the vein in your arm more visible and easier to access with a needle, a band called a tourniquet is placed around your upper arm.
- A needle is placed in your vein, and a test tube is attached to the needle which is then filled with blood. You may or may not feel a pinch or a little pain when the needle is inserted.
- Once the test tube or vial is filled, the needle and tourniquet are removed, and the test is over.
After the test
After the blood draw is over, the health care provider will place a band-aid or cotton swab over the area where the needle was inserted. They may instruct you to keep this in place for an hour or more.
Slight bruising, dizziness, or lightheadedness may be side effects after a blood draw. Uncommon side effects may include persistent bleeding, fainting, or tingling of hands and feet.
In some cases, your provider may have you stay for a few minutes after the blood draw to monitor you until they are sure you are safe to walk and/or drive.
MCH Test Results
Receiving test results
Depending on the laboratory equipment that is used, MCH results on CBC report may be available within a few days.
You will be able to access the report through your online health portal or a copy can be provided to you upon request. A health care provider can review your MCH results in relation to other blood measurements on your CBC and interpret what they mean for your health.
Interpreting test results
In order to appropriately interpret an MCH test, it must be compared to its reference range and also to the other results reported on a complete blood count. The reference range is the set of MCH values that are considered to be expected in a population of healthy adults. Each laboratory determines reference ranges according to their own equipment and patient population.
MCH is reported as picograms per cell (pg). The American Board of Internal Medicine lists a typical MCH count reference range as 28-32 pg/cell.
When MCH results fall outside of the reference range, it indicates that the amount of hemoglobin in your blood cells may be too low or too high. MCH that falls within the reference range may also be a sign of an underlying health condition, depending on the results of other red blood cell indices.
MCH in people with anemia may be reported as:
- Lower than MCHreference range: Low MCH is called hypochromic anemia. This type of anemia can be caused by iron deficiency or thalassemia, a genetic condition which causes your body to have less hemoglobin than it should.
- Within MCHreference range: Normochromic anemia can occur when MCH is within the reference range and may be caused by sudden blood loss, chronic disease, or kidney failure.
- Higher than MCH reference range: High MCH is called hyperchromic anemia, a condition that can be caused by low folate or vitamin B12 levels or chemotherapy.
Diagnostic interpretation of an MCH result is most commonly performed by comparing it to the other red blood cell indices, which include MCV, MCHC, and RDW. Collectively, these red blood cell indices can be used to diagnose and classify different types of anemia.
Your MCH levels may have implications for your health. If you discuss your results with your health care provider, you may wish to ask:
- What do my MCH levels indicate about my health?
- Can any diagnoses be made based on my MCH results?
- Do I need any follow-up tests based on my MCH results?
- If my test results are abnormal, should I make any changes to improve my health?
