- What Are MCH Levels in Blood Tests?
- High & Low Mean Corpuscular Hemoglobin Concentration (MCHC)
- What is MCHC?
- Normal MCHC
- Low MCHC
- Causes of Low MCHC
- 1) Iron Deficiency
- 2) Anemia of Chronic Disease
- 3) Thalassemia
- 4) Sideroblastic Anemia
- Increasing MCHC
- High MCHC
- Causes of High MCHC
- 1) Hemolytic Anemia
- 2) Vitamin B12 and Folate Deficiency
- 3) Hereditary Spherocytosis
- Decreasing MCHC
- MCH Levels: High and Low Symptoms, Treatments, and Risks
- What Are MCH Levels?
- Why Test MCH Levels?
- What Is the Normal Range for MCH?
- What Do Low MCH Levels Mean?
- Symptoms of Low MCH
- Treatment for Low Levels
- What Do High MCH Levels Mean?
- Symptoms of High Levels
- Treatment for High Levels
- Outlook for High or Low MCH Levels
- What Is Mean Corpuscular Hemoglobin Concentration (MCHC)?
- Understanding the Complete Blood Count (CBC)
- Reporting and interpreting the results
- Red Blood Cells (RBCs) – transporting oxygen throughout the body
- Other RBC measurements
- What this means to me and my doctor
- White Blood Cells (WBCs) – defending your body
- The differential – visualizing the cells
- Platelets – helping to clot blood
- Platelet Counts – assessing your body’s ability to clot blood
- Table: Items included in a CBC Test Report
What Are MCH Levels in Blood Tests?
You might hear your doctor talk about MCH levels when he explains the results of certain blood tests. MCH is short for “mean corpuscular hemoglobin.” It's the average amount in each of your red blood cells of a protein called hemoglobin, which carries oxygen around your body.
It's possible you'll learn about MCH when you get a blood test called a CBC (complete blood count). This test measures different parts of your blood, including red blood cells and white blood cells. Doctors use information from the CBC to calculate your MCH.
A similar measure to MCH is something doctors call “mean corpuscular hemoglobin concentration” (MCHC). MCHC checks the average amount of hemoglobin in a group of red blood cells.
Your doctor may use both measurements to help in a diagnosis of anemia. It's a condition caused by not having enough healthy red blood cells, or the red blood cells you do have don't work as well as they should. Anemia can make you feel extremely tired.
A CBC measures the different cells that make up your blood, including your:
- Red blood cells
- White blood cells, which fight infection
- Platelets, which help your blood clot
You may have a CBC as part of your yearly physical exam or to check for a disease. Your doctor might give you this test if you have symptoms of a condition that affects your blood cell count.
To do a CBC, a nurse puts a needle into a vein in your arm. The needle attaches to a test tube, where the blood collects. A lab then analyzes the blood sample.
Anemia can cause abnormal MCH readings on blood tests. Often a lack of iron causes anemia with a low MCH. Your body needs iron to make hemoglobin.
Pregnancy, blood loss, and weight loss surgery can all cause a drop in your iron levels and lead to iron-deficiency anemia or low hemoglobin and MCH levels.
When you have iron deficiency anemia, you may have symptoms :
An anemia with a high MCH level could also be a sign that you don't have enough vitamin B12 or other nutrients. Your body needs vitamin B12 to make healthy blood cells, nerves, and DNA.
Signs of low vitamin B12 include:
- Numbness or tingling in your hands and feet
- Trouble walking or staying balanced
- Trouble thinking
- Swollen tongue
An anemia with a high MCH is called macrocytic anemia. When you have this condition, your red blood cells are larger than normal.
Other causes of macrocytic anemia include:
Macrocytic anemia often doesn't cause symptoms. You may not know you have it until your doctor does a blood test for another reason.
If your body doesn't have enough vitamin B, you might have symptoms :
Some conditions, including high cholesterol and high triglycerides, can make your MCH level seem high on a test when they're not really. Your doctor will help you interpret the test results.
Which treatment you need depends on the condition that raised or lowered your MCH level.
If you have anemia, supplements can replace what your body lacks. You may also need treatment for the condition that caused your anemia. For example, if the cause is blood loss, birth control pills lessen heavy bleeding during periods. If you have a bleeding polyp or tumor, you may need surgery to remove it.
If your body doesn't have enough vitamin B12 or folate, your treatment will be to get more of these vitamins. They're in foods fish, liver, green leafy vegetables, and fortified cereals. If you're a vegetarian or you don't eat enough foods that have vitamin B12, you can take supplements or get regular B12 shots from your doctor.
American Society of Hematology: “Anemia.”
Case Reports in Neurological Medicine: “Reversible vitamin B12 deficiency presenting with acute dementia, paraparesis, and normal hemoglobin.”
Harvard Medical School: “The A list of B12 foods,” “Vitamin B12 deficiency can be sneaky, harmful.”
Indian Journal of Hematology & Blood Transfusion: “Evaluation of macrocytosis in routine hemograms.”
Mayo Clinic: “Anemia,” “Complete Blood Count (CBC),” “Iron deficiency anemia,” “Macrocytosis: What Causes It?”
Medscape: “Mean Corpuscular Hemoglobin (MCH) and Mean Corpuscular Hemoglobin Concentration (MCHC).”
National Heart, Lung, and Blood Institute: “Blood Tests.”
NHS: “Symptoms: Vitamin B12 or folate deficiency anemia.”
Sarma, P. Clinical Methods: The History, Physical, and Laboratory, Butterworths, 1990.
University of Rochester: “What Are Red Blood Cells?”
© 2019 WebMD, LLC. All rights reserved.
High & Low Mean Corpuscular Hemoglobin Concentration (MCHC)
MCHC can help diagnose different blood disorders, such as anemia. Keep reading to find out what causes high and low MCHC, and how to address them.
What is MCHC?
MCHC is normally a part of a complete blood count, which measures your red blood cells, white blood cells, and platelets.
Mean corpuscular hemoglobin concentration (MCHC) is the average amount of hemoglobin per red blood cell, relative to the size of the cell. In other words, it tells you what percentage of your blood cells are made up of hemoglobin, the protein that helps transport oxygen in the blood [1, 2].
Decreased MCHC causes hypochromia (“hypo-” = low, “chromia” = color), which makes the red blood cells paler. Meanwhile, increased MCHC causes red blood cells to become darker, also known as hyperchromia [2, 3].
In short, MCHC is an indirect measure of how much hemoglobin you have. The added value of this test over direct hemoglobin is that it adjusts for the rate of the production of red blood cells [4+].
In many cases, when hemoglobin production is reduced, the production of red blood cells is wise reduced. However, in some cases, hemoglobin production can be reduced, while red blood cell production can increase. This can help differentiate specific conditions from one another [4+].
Gut bleeding is an example where both hemoglobin and red blood cells may be reduced in a similar fashion, due to blood loss [4+].
However, in iron deficiency, hemoglobin can go down, while red blood cells can be less affected. In these cases, MCHC would be lower than when there is blood loss [4+].
MCHC normally ranges from 320 – 360 g/l .
There can be some lab-to-lab variability in ranges due to differences in equipment, techniques, and chemicals used.
A low mean corpuscular hemoglobin concentration (MCHC) can cause hypochromia, or paler red blood cells. Hypochromia is a sign of anemia .
However, a result that is slightly lower may not be of medical significance, as this test often varies from day to day and from person to person. Your doctor will interpret this result, taking into account your medical history and other tests, such as RBC, hemoglobin, and other red blood cell indices.
Causes of Low MCHC
Causes shown below are commonly associated with low MCHC. Work with your doctor or other health care professional to get an accurate diagnosis of the underlying cause.
1) Iron Deficiency
One of the most common causes of low MCHC is iron deficiency and iron deficiency anemia [6, 5]. Iron is necessary to produce hemoglobin, so if you are deficient in iron, you will produce less hemoglobin for each given red blood cell.
Iron deficiency can be due to a dietary deficiency, gut issues that decrease iron absorption (e.g. Celiac disease), or toxins that interfere with iron absorption (e.g. lead) [6, 5, 7].
2) Anemia of Chronic Disease
Many different types of infection can reduce MCHC, such as:
- Hookworm 
- H. Pylori 
- HIV 
Infections cause inflammation, which in turn causes people to produce less hemoglobin. Presumably, in these infections hemoglobin is being reduced more than red blood cells, so MCHC is lower.
Thalassemia is a blood disorder that causes abnormal hemoglobin production. People with alpha- and beta-thalassemia have lower MCHC than healthy people [11, 12, 13].
4) Sideroblastic Anemia
A rare genetic disorder called inherited sideroblastic anemia can decrease MCHC .
Work with your doctor to find out what’s causing your low MCHC and to treat any underlying conditions.
Attempting to raise MCHC artificially may not address underlying health conditions and ultimately may do more harm than good.
If you have a low MCHC, your doctor may order additional tests and/or use this result to help make a diagnosis and determine an appropriate course of action, which may or may not include the strategies below.
Discuss the strategies listed below with your doctor. None of them should ever be done in place of what your doctor recommends or prescribes!
Make sure your diet is well balanced and contains enough nutrients, especially iron. This will prevent nutritional deficiencies that can cause problems with red blood cells [6, 5]. However, remember that nutrient deficiencies can also have non-dietary causes, such as bleeding or gut issues (malabsorption), in which case they can’t be corrected by simple dietary adjustments.
Avoid drinking tea and coffee with meals. These decreasing the absorption of iron into the body [15, 16].
Discuss the following supplements with your doctor:
- Iron (if deficient) [6, 5]
- Vitamin C (if deficient in iron) – it increases the absorption of iron 
A high mean corpuscular hemoglobin concentration (MCHC) can cause hyperchromia, or darker colored red blood cells .
However, a result that is slightly higher may not be of medical significance, as this test often varies from day to day and from person to person. Your doctor will interpret this result, taking into account your medical history and other tests, such as RBC, hemoglobin, and other red blood cell indices.
Causes of High MCHC
Causes shown below are commonly associated with high MCHC. Work with your doctor or other health care professional to get an accurate diagnosis of the underlying cause.
1) Hemolytic Anemia
Hemolysis is the rupture or destruction of red blood cells. It is one of the most common causes of increased MCHC [18, 19]. This is because red blood cells are decreasing, while hemoglobin is relatively unchanged.
This type of anemia can occur due to various causes, including autoimmune anemia (e.g. cold agglutinin disease) [18, 1, 20].
2) Vitamin B12 and Folate Deficiency
Vitamin B12 and folate deficiency can increase MCHC [21, 22]. That’s because they can impair the production of red blood cells without affecting hemoglobin.
3) Hereditary Spherocytosis
Hereditary spherocytosis is a genetic condition in which red blood cells get destroyed and MCHC increases. People who have this disorder have significantly higher MCHC than healthy people .
Work with your doctor to find out what’s causing your high MCHC and to treat any underlying conditions! Attempting to decrease MCHC artificially may not address underlying health conditions and ultimately may do more harm than good. If you have a high MCHC, your doctor may order additional tests and/or use this result to help make a diagnosis and determine an appropriate course of action, which may or may not include the strategies below.
Remember to discuss the strategies listed below with your doctor. None of them should ever be done in place of what your doctor recommends or prescribes!
Make sure you eat a healthy diet that contains enough nutrients, especially vitamin B12 and folate. This will prevent nutritional deficiencies that can cause problems with red blood cells . However, keep in mind that nutrient deficiencies can also have non-dietary causes, such as gut issues (malabsorption), in which case they can’t be corrected by simple dietary adjustments.
Alcohol consumption can reduce B12 and folate levels [23, 24, 25]. Avoid alcohol if your MCHC is high due to vitamin B12 deficiency.
Smoking (nicotine) can also lower B12 and folate levels [26, 27], and is best reduced or avoided altogether.
If you are deficient in either B12 or folate, your doctor will ly prescribe supplements.
MCH Levels: High and Low Symptoms, Treatments, and Risks
What Are Normal MCH Levels Low MCH Levels High MCH Levels
What Are MCH Levels?
MCH levels reveal the average amount of hemoglobin in each red blood cell.
Hemoglobin is a protein that makes your blood red. It takes oxygen from your lungs to other parts of your body. It’s also what helps your body get rid of carbon dioxide.
Mean corpuscular hemoglobin, or MCH, is the average amount of hemoglobin in one of your red blood cells. It is not the same as MCHC. That’s your “mean corpuscular hemoglobin concentration.” It’s another measure of hemoglobin, but it takes into account how big or small your red blood cells are. The average size of the cells is mean corpuscular volume (MCV).
If your MCH levels are off, it’s normal to worry. But your doctor will order more tests to find out what’s going on. A lab technician may do a blood smear. That means the technician looks at your blood under a microscope. Your doctor will probably test your blood to see if you have enough vitamin B12, folate, and iron.
MCH that is either low or high can cause concern. But once the doctor determines what’s going on, she can take steps to address the issues. Here’s information to help you understand what’s going to happen when the doctor tells you your MCH is either higher or lower than it should be.
Why Test MCH Levels?
The MCH test is part of the complete blood count (CBC). That’s a set of tests that show the health of your blood cells. You may get a CBC as part of your yearly checkup. Or, your doctor may order one if you have symptoms of certain health problems.
The doctor may look closely at MCH — along with MCV and MCHC — if you show signs of anemia or certain nutritional deficiencies.
What Is the Normal Range for MCH?
On average, your MCH should be between 27.5 to 33.2 picograms (pg) per cell. Women’s MCH may be lower than men’s because women lose blood when they have a period.
What Do Low MCH Levels Mean?
Your MCH dips below normal when your body doesn’t make enough hemoglobin. One reason for this is microcytic anemia. That means your red blood cells are too small. Extremely low iron levels are usually the cause of this type of anemia.
You may be at risk for iron-deficient anemia if you:
Your MCH levels could also be low if your body doesn’t make enough healthy red blood cells — a condition called thalassemia. The name refers to a group of blood disorders that a person has at birth. You get it from your parents’ genes.
Symptoms of Low MCH
When you have low MCH, your red blood cells carry less oxygen through your body. That’s what makes you feel tired. You may also have:
Treatment for Low Levels
The treatment depends on what is causing your symptoms. If you have a mild lack of iron, your doctor may ask you to:
- Eat more food with iron
- Take iron pills
- Add vitamin C to your diet (to help you absorb iron)
- Quit drinking black tea (lowers iron absorption)
If you have a serious lack of iron, you may need:
- Intravenous (IV) iron therapy – iron medication infused into a vein
- A blood transfusion – someone else’s blood infused into your vein
You may not need any treatment if you have mild thalassemia. But if your condition is more serious, you may get:
- Blood transfusions
- Iron chelation therapy – medication that you swallow or receive via IV, which you may need if you have high iron from many transfusions
- Folic acid pills
Do not take iron supplements if you don’t have low levels of iron. It could hurt your organs.
What Do High MCH Levels Mean?
Your MCH will reflect your MCV. That means you’ll have more hemoglobin if your red blood cells are larger than normal. Red blood cells can grow too large when you have fewer of them than normal — a condition called macrocytic anemia. It’s more common if you’re elderly. Lifestyle or genetic factors can also cause it.
You may have high MCH if you have very low vitamin B12 or folate. These are B vitamins that help you make red blood cells. This may happen if:
- Your stomach can’t absorb vitamin B12 (pernicious anemia)
- You have all or part of your stomach removed (gastrectomy)
- You eat a vegan diet (plant foods have little to no B12)
- You have an autoimmune condition
Other causes include:
Certain medicines may cause your MCV and MCH levels to go up, including these types:
You may not have a health problem causing your high MCH. Let your doctor know if you have a family history of increased MCV or MCH. If doctors don’t find a cause, they may want to recheck your levels every six months.
Symptoms of High Levels
You may not feel bad if your MCH is high. But it may be a sign that your red blood cells aren’t dividing the right way. This may cause anemia because you end up with fewer red blood cells. You could have symptoms similar to low MCH. The most common one is tiredness.
If you don’t have enough vitamin B12, you might have:
Treatment for High Levels
low levels, your care depends on the cause of your symptoms. When your doctor finds out why you have high MCH, you may need:
- Vitamin B12 shots or pills
- A different type or dose of medicine
- Folic acid pills
If you have low B12, you may feel better within a few days of treatment. Make sure to check in with your doctor until your levels are back to normal. Too little B12 for too long can raise your risk of stomach cancer. It could also damage your:
- Digestive tract
Outlook for High or Low MCH Levels
Your doctor can help you monitor or treat whatever is causing your high or low MCH levels. Dietary or lifestyle changes might help. Or you could need a more serious treatment to get well. Your health care team can help find the right way to help you stay healthy.
(c)2019 WebMD, LLC. All rights reserved.
Sarma, P. Clinical Methods: The History, Physical, and Laboratory Examinations. 3rd edition, Butterworths, 1990.
Cleveland Clinic: “Executive Health Reference Guide.” American Society of Hematology: “Blood Basics,” “Iron-Deficiency Anemia.” American Association for Clinical Chemistry, Lab Tests Online: “Red Cell Indices,” “Complete Blood Count (CBC).”
Dean, L. Blood Groups and Red Cell Antigens, National Center for Biotechnology Information, 2005.
Chaudhry, H., Kasarla, M. Microcytic Hypochromic Anemia, StatPearls Publishing, 2019.
National Heart, Lung, and Blood Institute: “Thalassemias,” “Iron-Deficiency Anemia,” “Pernicious Anemia.” University of Rochester Medical Center: “Iron Deficiency After Gastric Bypass Surgery,” “Vitamin B-12 Deficiency Anemia,” “Folate-Deficiency Anemia.” CDC: “Thalassemia: Complications and Treatment.”
Clinical Medicine & Research: “Megaloblastic Anemia and Other Causes of Macrocytosis.”
Journal of General and Family Medicine: “Diagnosis and treatment of macrocytic anemias in adults.”
National Down Syndrome Society: “Blood Diseases & Down Syndrome.”
Medical Archives — Journal of The Academy of Medical Sciences in Bosnia and Herzegovina: “Effect of Cigarette Smoking on Haematological Parameters in Healthy Population.”
Blood: “The Significance of Unexplained Macrocytosis.”
Hariz, A., Bhattacharya, P. Megaloblastic Anemia, StatPearls Publishing, 2019.
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What Is Mean Corpuscular Hemoglobin Concentration (MCHC)?
Mean corpuscular hemoglobin concentration (MCHC) is lab value found on a complete blood count (CBC) that describes the average concentration of hemoglobin in a given volume of red blood cells.
Hemoglobin is what gives red blood cells their color, and therefore a higher concentration of hemoglobin with high MCHC makes the cells appear darker (hyperchromic) and a low concentration with low MCHC makes them appear lighter (hypochromic).
The value of MCHC is helpful in diagnosing anemia, but is used along with the red blood cell count (RBC) and other red blood cell indices such as MCV and RDW.
In addition to its role in evaluating blood disorders, MCHC may be helpful even when the red blood cell count is normal (in a person who doesn't have anemia), such as in helping doctors predict the prognosis after a heart attack and more.
Since the mean corpuscular hemoglobin concentration (MCHC) is done as part of a complete blood count (CBC), the test is done any time a CBC is ordered. This may include routine health screenings or during the diagnosis, treatment, and follow-up of a wide range of medical conditions.
Reasons a doctor may specifically look at the MCHC include:
- when symptoms of anemia are present such as fatigue, pale skin, or lightheadedness
- when looking for the different causes of anemia (when a person's red blood cell count (RBC) and/or hemoglobin levels are low)
- \when considering the prognosis of medical conditions such as heart attacks or lung cancers
MCHC is calculated by multiplying the hemoglobin level times ten and then dividing by the hematocrit level. The number is recorded in grams per liter.
- MCHC = Hb x 10 / hematocrit
MCHC may also be calculated by dividing the mean corpuscular hemoglobin by the mean corpuscular volume:
The mean corpuscular hemoglobin concentration is a measure of the concentration of hemoglobin in cells.
Since hemoglobin is the molecule to which oxygen attaches, MCHC is a measure of the average oxygen carrying capacity of the red blood cells circulating in the body.
A low MCHC (hypochromia) means that there is a lower concentration of hemoglobin within a given volume of red blood cells, and hence, a reduced capacity to carry oxygen to the tissues. A normal (normochromia) or high MCHC (hyperchromia) means that the oxygen-carrying capacity of the red blood cells is normal, but it may still be deficient if not enough red blood cells are present.
There are several limitations that can affect the accuracy of the MCHC reading including.
Since blood drawn after a blood transfusion will be a mixture of donated cells plus a person's normal red blood cells, the MCHC won't give accurate information about the original red blood cells present.
If a person has two different types of anemia that lead to different MCHC levels, the reading won't be as helpful in diagnosing the type of anemia. For example, the MCHC may be normal if a person has a combination of iron deficiency anemia (which causes a low MCHC) and spherocytosis (which tends to cause a high MCHC).
Conditions that Give Inaccurate Hemoglobin or Hematocrit levels
Since MCHC is calculated using the hemoglobin and hematocrit, anything that falsely increases or decreases these numbers will give a false MCHC result.
For example, hyperlipidemia (an increased level of cholesterol or triglycerides), hyperbilirubinemia (elevated bilirubin levels in the blood as with liver disease), and autoagglutination will cause the hematocrit level to be falsely high and the hemoglobin levels to be falsely low.
With hemolysis (breakdown of red blood cells), free hemoglobin in the plasma that is left over from the broken red blood cells will also cause an abnormal result—the MCHC will be falsely increased.
The mean corpuscular hemoglobin (MCH) test measures the average mass of hemoglobin per red blood cell. While the name sounds similar to MCHC, it actually provides information that is more similar to the MCV (mean corpuscular volume or MCV affects the amount of hemoglobin in the cell).
Many physicians consider MCH to be the least helpful of the red blood cell indices and look primarily at the MCV in this setting. When compared with MCH, MCHC is a much better test for detecting hypochromia.
- Mean corpuscular volume (MCV): MCV is a measure of the average size of the red blood cells
- Red cell distribution width (RDW): RDW is a number that reflects the variation in sizes of the red blood cells
- Mean corpuscular hemoglobin (MCH): MCH is the average mass of hemoglobin per red blood cell
In addition, other tests may be done such as a peripheral blood smear for morphology and reticulocyte count, and when indicated, iron studies, vitamin B12 levels, and more may be needed to further clarify information found on the CBC.
There are a few potential risks to having a CBC performed, including a small risk of bleeding, bruising, and infection.
There are no dietary or activity restrictions prior to having a CBC. It's important to bring your insurance card to your appointment and to make sure your doctor has access to prior CBCs you have had for comparison.
The test can be conducted in many hospitals and clinics. Prior to drawing your blood, a lab technician will cleanse the area (usually a vein in the arm) with an antiseptic and a tourniquet is applied to better visualize the vein. If you have a chemotherapy port, blood can be drawn directly from the port.
The technician will then insert the needle into a vein. You may feel a sharp poke when the needle enters, and some pressure as it remains in place. Some people may feel lightheaded or faint with the needle stick. Make sure to let the technician know if you are feeling lightheaded. After obtaining the sample, the technician will remove the needle and ask you to hold pressure over the site.
When the bleeding has stopped, a bandage will be applied or gauze wrapped around your arm to keep the area clean and to reduce the chance of further bleeding.
When the test is done, you will be able to return home and resume your regular activities. Potential side effects include:
- pain from the needle stick, especially if many attempts are made
- difficulty obtaining a specimen from a blood draw (such as in people whose veins are difficult to access due to chemotherapy)
- bleeding (bleeding can take longer to stop in people who are on blood thinners or have a bleeding disorder)
- hematoma or a large bruise may form and can be uncomfortable, but it is very uncommon
- infection (when the skin is penetrated, there is a small risk of bacteria being introduced into the body)
If your clinic has a lab on site, you may receive your results shortly after they are drawn. Other times, your doctor may call you to give you your results. It's important to be your own advocate and ask for the actual numbers (for example, your MCHC) rather than whether your CBC is simply normal or not.
The “normal” range for MCHC can vary somewhat between different labs but is usually between 32 and 36. Some labs have a smaller range of normal, for example, between 33.4 and 35.5.
The MCHC is calculated from hemoglobin and hematocrit, so anything that interferes with these numbers will make the MCHC inaccurate. Results will also be inaccurate after a transfusion (they will reflect the characteristics of the transfused cells combined with a person's own cells).
MCHC may be normal with many types of anemia (normochromic anemias) such as:
- blood loss anemia
- anemia due to kidney disease
- mixed anemias
- bone marrow failure
- hemolytic anemias (many types)
When the MCHC is low (unless the result is inaccurate due to one of the limitations noted earlier), it means that the red blood cells do not have enough hemoglobin. Possible causes include:
- Iron deficiency (with or without anemia)
- Lead poisoning
- Thalassemias (beta thalassemia, alpha thalassemia, and thalassemia intermedia)
- Sideroblastic anemia
- Anemia of chronic disease
A low MCHC without anemia is associated with poor outcomes for people in intensive care. It may also indicate iron deficiency before anemia develops.
A high MCHC means that hemoglobin is more concentrated than usual and may occur in a few ways. For instance, hemoglobin becomes more concentrated with red blood cells break down. MCHC is often increased in people who smoke. MCHC may also be falsely increased due to cold agglutinin disease
Potential causes of a high MCHC with anemia include:
- Autoimmune hemolytic anemia (due to medications, autoimmune conditions, and more)
- Hereditary spherocytosis
- Severe burns
- Liver disease
- Sickle cell disease (homozygous)
- Hemoglobin C disease
MCHC results are most helpful when used in conjunction with other red blood cell indices, especially mean corpuscular volume (MCV).
For instance, low MCHC and low MCV could indicate iron deficiency anemia, thalassemia, sideroblastic anemia, or lead poisoning. A high MCHC and low MCV could indicate spherocytosis or sickle cell disease.
Normal MCHC and high MCV could mean a vitamin B12 or folate deficiency or liver disease.
In addition to blood counts and red blood cell indices, additional tests that may be needed include:
- Peripheral Blood Smear for Morphology: A peripheral smear involves looking at the blood sample under the microscope. This allows the technician to directly visualize other changes in the red blood cells that may be associated with anemia such as target cells, nucleated red blood cells, and more.
- Iron Studies: Serum iron and iron-binding capacity and/or ferritin levels can give valuable information on iron stores and can help discriminate iron deficiency from other anemias with a low MCHC.
- Vitamin B12 Level: Vitamin B12 levels are helpful in looking for pernicious anemia.
- Bone Marrow Aspiration and/or Biopsy: In some cases, a bone marrow study may be needed to assess the appearance of blood cells in the bone marrow and iron stores.
Historically, red blood cell indices were used primarily in characterizing anemias, but these numbers may provide important information even when there are no signs of anemia.
One study found that MCHC was useful in estimating the prognosis after myocardial infarction. In this setting, MCHC appears to be an independent measure of both short term and long term prognosis after a heart attack.
A low MCHC may predict survival with lung cancer as well. In people undergoing surgery for lung cancer, those who were not anemic but had a lower MCHC had a poorer survival rate (by a factor of 42 percent) than those with a normal MCHC.
In addition to physical conditions, MCHC may play a role in the assessment of mental health as well. One study found that MCHC was helpful in predicting the risk of future depression in women.
Mean corpuscular hemoglobin concentration (MCHC) is most meaningful when combined with other results on a CBC and can be helpful in discriminating causes of anemia as well as predicting prognosis in those without anemia. When using these results, however, it's very important to be aware of the limitations as well as the potential of error and to use any findings only after they are repeated and supported by other studies.
Understanding the Complete Blood Count (CBC)
The human body is primarily made up of water and cells. Many of the cells group together to form the skin, muscles, bones and organs, such as the heart, lungs, kidneys, etc. Such cells are stationary, staying in one place within the body.
Some very special and important cells, however, move throughout the body by traveling (circulating) in the blood. These circulating cells provide oxygen to all of the stationary cells in the body, help fight infection throughout the body, and help stop bleeding after an injury.
Information about these cells can provide important clues about the overall health of the body.
The complete blood count, or CBC, is a lab test that provides information about these circulating cells. First, a sample of your blood is collected and sent to the lab.
A lab instrument then automatically counts the number of each type of circulating cell.
If results from the automated instrument are outside specified limits, a medical technologist will examine the cells closely so complete information about the cells can be provided.
Results from the CBC test can help:
- Provide basic information about your health
- Detect a health condition before you have any symptoms
- Confirm that a health condition exists
- Identify the causes of your symptoms
- Find out if your medicine is working
- Rule out a disease
- Establish a baseline that can be used for comparison with future test results
Reporting and interpreting the results
Your CBC test results are usually reported along with a reference range of expected or desired values to help guide your doctor in interpreting them.
Reference ranges reflect the numeric values found in healthy people; however, a small number of healthy people (5%) have values that are higher or lower than the ones shown in the reference range.
Thus, values higher or lower than those in the reference range might or might not indicate a medical condition.
In addition to the reference range, your doctor will consider other factors when interpreting your CBC test results.
These factors include your personal and family medical history, results from a physical exam, and other test results.
Your doctor will also consider factors that might cause an incorrect test result such as improper sample collection or handling. Therefore, it’s important that you talk with your doctor about the meaning of your test results.
This brochure includes a brief description of the items included in the CBC test report. The descriptions can help you understand your results so you can have a more meaningful discussion with your doctor. Additionally, items in the CBC are summarized in the table at the end of this brochure for quick reference.
Red Blood Cells (RBCs) – transporting oxygen throughout the body
RBCs play a vital role in transporting oxygen from the lungs to the rest of the body.
These oval-shaped cells contain hemoglobin, the protein that binds oxygen while it is being carried to all the stationary cells in the body (cells in the skin, muscle, bone and organs).
The chemical process that converts the nutrients found in food into energy requires oxygen. All the stationary cells require energy to function; thus, they need oxygen and are dependent on the RBCs to transport it.
Hemoglobin (Hb or Hgb) is an iron-rich protein that carries oxygen and makes the blood red. Since hemoglobin is contained only in the RBCs, a low number of RBCs leads to low levels of hemoglobin.
However, if there is something wrong with the RBCs, hemoglobin levels can be low even when the RBC count (i.e. number of RBCs) is within the reference range.
So a CBC test report includes the number of RBCs, the amount of hemoglobin, and other measurements related to the RBCs.
Other RBC measurements
The hematocrit reflects the amount of space in the blood that is occupied by RBCs. Hematocrit measurements are affected by the number of RBCs and by the size of the RBCs.
The mean corpuscle (cell) volume (MCV) is a measurement of the average size of the RBCs. Small-sized RBCs result in a lower MCV, while larger RBCs result in a higher MCV.
The mean corpuscular hemoglobin (MCH) reflects the average amount of hemoglobin in a person’s RBCs. RBCs with more hemoglobin result in a higher MCH and vice versa.
The mean corpuscular hemoglobin concentration (MCHC) is a measurement of the average amount of hemoglobin in the RBCs compared to the average size of the RBCs. Put another way, the MCHC is the ratio of the MCH to the MCV.
The red cell distribution width (RDW) reflects the degree of variation in size of the RBCs. Not all the RBCs are the same size; some are larger and some are smaller. The RDW measurement is affected by the size of the smallest RBC and the size of the largest RBC.
What this means to me and my doctor
In patients with anemia, hemoglobin levels are low and the patient may be frequently tired and have little energy. This is because there is not enough hemoglobin to carry oxygen to the stationary tissues; thus, there is not enough oxygen available to convert nutrients into energy. The RBC count, hematocrit level, MCV, MCH and MCHC might also be low in patients with anemia.
Low RBC counts, hemoglobin and hematocrit levels can be caused by other things too, such as a lot of bleeding or malnutrition (not enough nutrients in the food eaten). Kidney disease, liver disease (cirrhosis), cancer, and medications used to treat cancer can also cause low levels.
An increased RBC count and increased levels of hemoglobin and hematocrit may be caused by dehydration (not enough water in the body) or by some diseases (see table).
White Blood Cells (WBCs) – defending your body
WBCs help the body fight illness or infection. As part of the immune system, they recognize and fight things that are foreign to (not part of) the body. The number of WBCs (WBC count) is lower than the number of RBCs; however, the WBCs are larger in size RBCs. There are 5 types of WBCs; each type plays a different role in protecting the body from invaders.
The differential – visualizing the cells
When performing a differential, a medical technologist looks at the various cells under a microscope. A differential provides information about the relative numbers (that is, the percentage) of each type of WBC.
Such information helps the doctor determine whether an illness is caused by a bacteria, a virus, or leukemia.
A differential can be used to monitor patients with allergies and to determine how a patient is recovering from an illness or responding to therapy.
In addition to the cell types listed previously, certain cell types that don’t normally appear in the blood can be reported in the differential. These cells include promyelocytes, metamyelocytes, blasts, etc.
Presence of any of these cells indicates a need for follow-up with your doctor.
Finally, the differential can provide information about the appearance of RBCs, since the cells are visualized under a microscope.
The appearance of RBCs helps differentiate the various types of anemia.
Platelets – helping to clot blood
Platelets are the smallest blood cells. They are an important part of blood clotting. These small cells clump together and form a sticky mass that helps the blood to clot.
Blood clots help your body handle injury by stopping or preventing bleeding.
Blood clots can also cause problems, however, when they occur within the blood vessels or the heart; such clots cause a blockage known as thrombosis.
Platelet Counts – assessing your body’s ability to clot blood
A CBC includes the number of platelets and the mean platelet volume (MPV). MPV is a measurement of the average size of the platelets. A higher MPV roughly indicates better platelet function. Some medical conditions are associated with a high MPV and some are associated with a low MPV. Thus, the MPV can sometimes be helpful in telling apart different disorders.
A decreased number of platelets (thrombocytopenia) is associated with bleeding. Some causes include certain rare inherited disorders, leukemia, autoimmune disorders (e.g., rheumatoid arthritis or lupus) and medications.
A falsely low platelet count, which is not associated with bleeding, can be caused by a rare error in blood sample collection: instead of staying in a liquid form, the sample clots (becomes solid), thus using up the platelets.
An increased platelet count is less common and is associated with clotting disorders such as thrombocythemia. Platelet counts can also be increased in some cancers and following infections or other medical conditions.
Aspirin can decrease the platelet function, so it’s important to consult with your doctor when taking large amounts of aspirin or when taking aspirin for an extended period of time. Many over-the-counter medications contain aspirin, which may be listed as acetylsalicylic acid, salicylate, or 2-(acetyloxy) benzoic acid.
Table: Items included in a CBC Test Report