Understanding Your High MCHC Blood Test Results

Direct answer: High Mean Corpuscular Hemoglobin Concentration (MCHC) indicates that your red blood cells have a higher-than-normal concentration of hemoglobin. This can be caused by conditions that make red blood cells smaller or more fragile, leading to hemoglobin becoming more concentrated. The most common cause is hereditary spherocytosis, an inherited disorder affecting red blood cell shape. Other causes include autoimmune hemolytic anemia, severe burns, and certain liver diseases. Further testing is needed to determine the specific underlying cause.

TL;DR A high MCHC (Mean Corpuscular Hemoglobin Concentration) on your complete blood count (CBC) test means the hemoglobin inside your red blood cells is more concentrated than usual. Hemoglobin is the protein that carries oxygen, and this result suggests an issue with the size, shape, or integrity of your red blood cells. While it can be concerning, a high MCHC value is a clue that helps your doctor investigate further, not a diagnosis on its own.

• Primary Cause: Hereditary Spherocytosis: This is the most common reason for a consistently high MCHC. It's a genetic condition where red blood cells are abnormally small and spherical instead of disc-shaped, making them fragile and concentrating the hemoglobin.

• Autoimmune Hemolytic Anemia: In this condition, the immune system mistakenly attacks and destroys red blood cells. This process can lead to the formation of spherocytes and a resulting high MCHC.

• Severe Burns: Extensive burns can cause significant damage to red blood cells and lead to dehydration, both of which can artificially elevate MCHC levels.

• Red Blood Cell Agglutination: Sometimes, red blood cells clump together (agglutination), often due to specific antibodies. Lab equipment may misread these clumps, leading to a falsely high MCHC reading.

• Other Potential Factors: Less common causes include certain types of liver disease and rare red blood cell enzyme deficiencies.

• What Happens Next: A high MCHC result will prompt your healthcare provider to order additional tests, such as a peripheral blood smear to visually inspect the cells, to identify the exact cause and determine the appropriate treatment plan.

Want the full explanation? Keep reading ↓

What Does a High MCHC Level Mean?

A high Mean Corpuscular Hemoglobin Concentration (MCHC) indicates that the concentration of hemoglobin inside your red blood cells is higher than normal. Hemoglobin is the vital protein that carries oxygen, and MCHC is a standard measurement included in a Complete Blood Count (CBC) panel. Think of it as a measure of how "packed" each red blood cell is with hemoglobin.

While a high MCHC can sometimes point to a specific underlying medical condition, it can also be the result of a laboratory error. Your doctor will interpret this value in the context of your other CBC results, such as your red blood cell count (RBC), hemoglobin (Hgb), and hematocrit (Hct), as well as your overall health and symptoms. For a foundational understanding, you can explore the role of the [MCHC blood test and how the concentration of hemoglobin is explained].

A genuinely high MCHC is less common than a low MCHC and often prompts a closer look at the size and shape of your red blood cells. It signals that the normal balance of water and hemoglobin within the cell may be disrupted.

Is Your High MCHC Result Accurate? Understanding Potential Lab Errors

Before exploring medical causes, it's crucial to consider that a high MCHC can be a "false flag"—an artifact of the testing process rather than a true reflection of your physiology. Automated hematology analyzers are highly sophisticated, but certain conditions can interfere with their measurements, artificially elevating the MCHC value.

Your healthcare provider and the laboratory team are trained to spot these issues, which often trigger automatic reviews or repeat testing.

Common Causes of Falsely High MCHC

• Cold Agglutinins: This is the most frequent cause of a falsely elevated MCHC. Cold agglutinins are antibodies that cause red blood cells to clump together at cooler, room-temperature conditions. The analyzer may mistakenly count these clumps as single, large cells, leading to inaccurate RBC and MCV values, which in turn falsely inflates the calculated MCHC.
• Lipemia (High Blood Fats): A high concentration of lipids (fats) in the blood plasma can make the sample cloudy or turbid. This turbidity interferes with the light-based method used to measure hemoglobin, leading to a falsely high hemoglobin reading and, consequently, a high MCHC. This can occur if you've recently eaten a fatty meal before your blood draw or if you have a disorder of lipid metabolism.
• In Vitro Hemolysis: If red blood cells rupture within the collection tube (in vitro) due to a difficult blood draw or improper handling, the free hemoglobin released into the plasma can interfere with measurements, potentially skewing the MCHC result upward.

If a lab artifact is suspected, the laboratory will typically perform corrective procedures, such as warming the blood sample to disperse cold agglutinins, before re-analyzing the specimen.

High MCHC Reference Ranges: What's Considered Elevated?

To understand if your MCHC is high, you need to compare it to the established reference range. These ranges can vary slightly between laboratories depending on the equipment and population they serve. Always refer to the specific range provided on your lab report.

For general guidance on how MCHC values are typically categorized, a [normal MCHC range interpretation guide] can provide additional context. An MCHC value is generally considered high when it exceeds the upper limit of the normal range, which is typically around 36 g/dL.

Note: Values are typically reported in grams per deciliter (g/dL) or grams per liter (g/L). An MCHC above 36 g/dL is often flagged as high.

Concerned About Red Blood Cell Shape? The Link Between High MCHC and Spherocytosis

If lab errors are ruled out, the most classic medical reason for a true high MCHC is the presence of spherocytes. Spherocytes are abnormal red blood cells that have lost their typical biconcave disc shape and have become spherical.

A normal red blood cell is like a flattened disc, which provides a large surface area to facilitate oxygen exchange. A spherocyte, being a sphere, has the smallest possible surface area for a given volume. This geometric change means the hemoglobin inside is packed into a smaller, tighter space, leading to a higher concentration—and thus a high MCHC.

The presence of spherocytes almost always indicates a hemolytic process, meaning that red blood cells are being destroyed prematurely. This can be caused by either inherited or acquired conditions.

Hereditary Spherocytosis (HS)

Hereditary Spherocytosis is the primary inherited disorder associated with a high MCHC. It is a genetic condition that affects the structural proteins of the red blood cell membrane.

• What happens: Defects in proteins like ankyrin, spectrin, or band 3 weaken the cell's "skeleton." This instability causes the cell to lose bits of its membrane over time, forcing it into the more compact, spherical shape.
• Why it matters: These rigid, spherical cells are less flexible than normal red blood cells. They struggle to pass through the narrow passages of the spleen's filtration system, where they become trapped and destroyed by immune cells called macrophages.
• Key Signs and Symptoms:
  • Anemia: Varying from mild to severe, causing fatigue, pallor, and shortness of breath.
  • Jaundice: Yellowing of the skin and eyes due to high levels of bilirubin, a byproduct of red blood cell breakdown.
  • Splenomegaly: An enlarged spleen, which is working overtime to clear the abnormal cells.
  • Gallstones: The high bilirubin levels can lead to the formation of pigment gallstones, even in young individuals.

Autoimmune Hemolytic Anemia (AIHA)

Autoimmune Hemolytic Anemia is the most common acquired condition that leads to spherocytosis and a high MCHC. In AIHA, the body's own immune system mistakenly produces antibodies that attack its red blood cells.

• What happens: These antibodies coat the surface of red blood cells. When these coated cells pass through the spleen, macrophages recognize the antibodies as a "foreign" signal. They "bite off" a piece of the red blood cell's membrane, and the damaged cell reseals itself into a smaller, spherical shape (a microspherocyte).
• Why it matters: This process, called extravascular hemolysis, leads to the rapid destruction of red blood cells, causing anemia.
• Key Signs and Symptoms:
  • Often has a rapid onset.
  • Severe fatigue, weakness, and shortness of breath.
  • Dark, tea-colored urine due to hemoglobin breakdown products.
  • Jaundice and an enlarged spleen.
  • AIHA can be a primary condition or secondary to other illnesses like lupus, lymphoma, or certain infections.

Distinguishing Hereditary vs. Acquired Spherocytosis

While both conditions lead to spherocytes and high MCHC, your doctor will use your history, physical exam, and specific lab tests to tell them apart. A key test is the Direct Antiglobulin Test (DAT), also known as the Coombs test, which is positive in AIHA but negative in Hereditary Spherocytosis.

Beyond Spherocytosis: Other Conditions That Cause a True High MCHC

While spherocytosis is the hallmark cause, a few other, rarer conditions can also result in a genuinely high MCHC by causing red blood cell dehydration.

• Hereditary Xerocytosis: This is a rare genetic disorder affecting ion channels in the red blood cell membrane. The defect causes the cell to leak potassium, leading to a net loss of water. This cellular dehydration concentrates the hemoglobin inside, significantly increasing the MCHC.
• Severe Burns: In patients with extensive and severe burns, red blood cells can be directly damaged by heat. This thermal injury can cause the cells to fragment and form microspherocytes, which can raise the overall MCHC value.
• Sickle Cell Disease: While typically associated with normal or low MCHC, the pathophysiology of sickle cell disease involves cellular dehydration. Dehydrated, dense sickle cells have a very high intracellular hemoglobin concentration, which promotes the sickling process. Advanced analyzers may detect this subpopulation of very dense cells.

What to Expect After a High MCHC Result: Your Next Steps

Receiving a lab result showing a high MCHC can be concerning, but it's the beginning of an investigative process, not a final diagnosis. Here is a step-by-step guide on what to expect.

Step 1: Consultation with Your Doctor Your first and most important step is to discuss the result with your healthcare provider. They will evaluate your MCHC in the context of your complete CBC and your personal health history. Be prepared to discuss any symptoms you're experiencing, such as fatigue, jaundice, or shortness of breath.

Step 2: Peripheral Blood Smear Review This is often the immediate next step. A drop of your blood is spread on a glass slide, stained, and examined under a microscope by a pathologist or laboratory scientist. This crucial test allows for direct visualization of your red blood cells.

A blood smear can confirm:

• The presence, absence, and degree of spherocytes.
• Other abnormal red blood cell shapes, like sickle cells.
• Evidence of red blood cell clumping (agglutination).

Step 3: Further Diagnostic Testing Based on the initial findings, your doctor may order more specific tests to pinpoint the cause:

Step 4: Developing a Treatment Plan Treatment is directed at the underlying cause of the high MCHC, not the lab value itself.

• For Autoimmune Hemolytic Anemia (AIHA): Treatment often involves corticosteroids (like prednisone) or other immunosuppressive drugs to stop the immune system from attacking red blood cells.
• For Hereditary Spherocytosis (HS): Management depends on severity. Mild cases may only require folic acid supplementation. More severe cases might require blood transfusions or splenectomy (removal of the spleen) to reduce red blood cell destruction.
• For Lab Artifacts: If the high MCHC was due to a lab error like cold agglutinins, no treatment is needed. Your doctor will simply rely on the corrected lab report.

Frequently Asked Questions

What is the most common cause of abnormal MCHC levels?

The most common cause of a falsely high MCHC is a laboratory artifact, most often cold agglutinins, which cause red blood cells to clump during testing. When it comes to true medical conditions, the most common causes of a high MCHC are conditions that produce spherocytes—abnormally spherical red blood cells. These include Autoimmune Hemolytic Anemia (AIHA) and the genetic disorder Hereditary Spherocytosis.

How often should I get my MCHC tested?

Your MCHC is not typically tested in isolation. It is part of the Complete Blood Count (CBC), one of the most common blood tests ordered during routine health check-ups, before surgery, or when investigating symptoms like fatigue or infection. If you have no underlying medical conditions, your doctor may order a CBC as part of your annual physical. If you have a diagnosed condition that affects red blood cells, such as hemolytic anemia, your doctor will establish a specific monitoring schedule to track your disease activity and response to treatment, which could be as frequent as weekly or as spread out as every few months.

Can lifestyle changes improve my MCHC levels?

For a truly high MCHC caused by a medical condition like Hereditary Spherocytosis or Autoimmune Hemolytic Anemia, lifestyle changes will not correct the underlying problem. The MCHC reflects the physical characteristics of your red blood cells, which are determined by genetics or an autoimmune process. Treatment must be directed by a physician to manage the specific disease. However, if you have a condition causing hemolysis, supporting your overall health with a balanced diet rich in folate and B vitamins is important for producing new red blood cells. If your high MCHC was falsely elevated due to high blood fats (lipemia), then lifestyle changes like a low-fat diet and exercise to manage cholesterol and triglycerides could prevent future lab errors.