Mean Corpuscular Hemoglobin Concentration, or MCHC, is a standard measurement included in a routine complete blood count (CBC). It specifically measures the average concentration of hemoglobin inside a single red blood cell. Hemoglobin is the iron-rich protein responsible for transporting oxygen throughout the body. An MCHC value is one of several red blood cell indices, alongside measurements like mean corpuscular volume (MCV) and red cell distribution width (RDW), that provide information about the health and function of these cells. A high result is not a diagnosis in itself, but it signals that further investigation may be necessary.
Understanding High MCHC Results
A high MCHC value indicates that the concentration of hemoglobin within red blood cells is higher than average, a state referred to as hyperchromia. Laboratories consider a normal MCHC to be between 32 and 36 grams per deciliter (g/dL), although this range can vary slightly depending on the lab.
Not all high MCHC readings point to a medical condition, as certain technical factors can artificially inflate the result. For instance, the presence of cold agglutinins, which are antibodies that cause red blood cells to clump together at lower temperatures, can interfere with automated counters and produce a falsely high MCHC. A high concentration of fats in the blood, a condition called lipemia, can also skew the test results and lead to an inaccurate reading.
Potential Causes of Elevated MCHC
An accurate high MCHC result often points to specific underlying medical conditions. One of the most common causes is hereditary spherocytosis, a genetic disorder that affects the structural proteins of the red blood cell membrane. This defect causes the cells to become sphere-shaped rather than the typical biconcave disc, reducing their surface area and concentrating the hemoglobin inside, which elevates the MCHC.
Another cause is autoimmune hemolytic anemia. In this condition, the body’s immune system mistakenly produces antibodies that attack and destroy its own red blood cells. As these cells are broken down prematurely, changes in their structure can lead to an increased concentration of hemoglobin within the remaining or fragmented cells, resulting in a higher MCHC value.
Less frequently, other conditions can be associated with an elevated MCHC. Patients who have suffered severe burns may show a temporary increase. The extensive tissue damage and fluid loss can lead to changes in blood concentration and red blood cell characteristics. Advanced liver disease can also impact red blood cell production and survival, sometimes leading to a higher MCHC.
Associated Symptoms
A high MCHC value does not produce symptoms on its own. Instead, any symptoms a person experiences are a direct result of the underlying condition causing the MCHC elevation. In conditions like autoimmune hemolytic anemia or hereditary spherocytosis, the primary issue is the premature destruction of red blood cells, which leads to a state of anemia and related signs.
Common symptoms stemming from these underlying disorders include:
- Persistent fatigue and weakness
- Shortness of breath, especially with exertion, and dizziness
- Jaundice, a noticeable yellowing of the skin and the whites of the eyes
- An enlarged spleen, or splenomegaly, as this organ works overtime to filter out the damaged red blood cells from circulation
Diagnostic Process and Treatment Approaches
An elevated MCHC prompts a physician to conduct a more thorough evaluation. The first step is to review the entire CBC panel, looking at other red blood cell indices for a more complete picture. A peripheral blood smear is a common follow-up test, where a drop of blood is examined under a microscope. This allows for direct visual inspection of the red blood cells to identify abnormalities, such as the sphere-shaped cells seen in hereditary spherocytosis.
Further testing may be required to pinpoint a specific diagnosis. A Coombs test can be ordered to detect antibodies attached to red blood cells, which would suggest autoimmune hemolytic anemia. A reticulocyte count measures the number of young red blood cells being produced, helping to determine if the bone marrow is responding properly to the anemia.
Treatment is not aimed at lowering the MCHC number itself but at managing the root cause. For individuals with hereditary spherocytosis, folic acid supplementation is often recommended to support the production of new red blood cells. In cases of autoimmune hemolytic anemia, treatment may involve immunosuppressive medications to stop the immune system’s attack on red blood cells.