Generality
The Medium Corpuscular Hemoglobin Concentration ( MCHC, from the English " Mean Corpuscolar Hemoglobin Concentration ") is the measurement of the amount of hemoglobin (Hb) present in every single red blood cell, in relation to the size of the erythrocyte itself.
In the laboratory, the value of MCHC is supplied automatically by the electronic cell counts, but can also be calculated according to the formula: Hb (g / dl) x 100 / hematocrit value .
The interpretation of the MCHC result has an important utility in the diagnosis and monitoring of numerous pathological conditions, including hypochromic anemias, vitamin B12 deficiencies and thyroid dysfunction .
What's this
MCHC: what is it?
- MCHC is the measure of hemoglobin concentration in a single red blood cell, depending on the size of the latter.
- The determination of this parameter is part of routine blood tests ; the test that allows to establish the value of MCHC is the blood count (also known as a blood count ).
- The result is expressed as a percentage and must be compared with the other values relating to red blood cells and hemoglobin.
- The term " Medium Corpuscular Hemoglobin Concentration " comes from the English " Mean Corpuscular Hemoglobin Concentration ", from which the acronym MCHC indicated in clinical reports.
Hemoglobin: what is it and what role does it play?
Hemoglobin ( Hb ) is a protein contained within red blood cells, specializing in the transport of oxygen to various parts of the body. In a healthy adult, his concentration should not fall below 12 g / dl. The reduction of hemoglobin, associated with that of red blood cells in the bloodstream, involves the symptoms that characterize anemia.
Corpuscular indexes: what and what are they?
MCHC is an erythrocyte index (also called corpuscular index of red blood cells ) which allows the analysis of the corpuscular part of the blood, that is of the cells circulating in the blood stream; in detail, this parameter relates the quantity of hemoglobin and the size of the erythrocyte cell.
MCHC provides, therefore, useful information about the appearance and characteristics of red blood cells (or erythrocytes), in combination with the medium corpuscular hemoglobin content ( MCH : coincides with the content, in terms of weight, of hemoglobin in each single red blood cell ) and the average corpuscular volume ( MCV : is the measure of the average size of red blood cells). The mean corpuscular hemoglobin concentration ( MCHC ) measures the concentration of hemoglobin in a single red blood cell, depending on the size of the latter.
MCHC, MCV and MCH are three parameters traditionally used to make a differential diagnosis of anemia .
To learn more: MCV and Anemia - Clinical Significance »Difference between MCH and MCHC
- MCH : indicates an absolute value in terms of weight - expressed in picograms - for each red blood cell, which is not related to the size of the latter; the normal values of MCH are between 26 and 32 picograms ;
- MCHC : is a ratio, therefore a relative value - expressed as a percentage - which relates the hemoglobin content to the size of the red blood cell in which it is contained. The MCHC can be calculated manually by dividing the hemoglobin / dl value by the hematocrit; the reference values are between 32 and 36% .
Why do you measure
MCHC: what's the use?
The analysis of the MCHC and, more generally, of the corpuscular indexes is prescribed when the patient manifests a certain number of signs and symptoms that can be related to pathologies that affect blood cells .
The result of the examination of the erythrocyte indices is useful in the framing of numerous forms of anemia characterized or not by variation of the MCV ( normocytic, microcytic or macrocytic anemias ) and / or of the quantity and concentration of hemoglobin within the red blood cells ( normochromic or hypochromic anemias ).
MCHC: when is the examination prescribed?
During a diagnostic procedure, the doctor can indicate the execution of the blood count with the MCHC analysis to identify the exact cause and / or determine the severity of a particular clinical picture. The mean corpuscular hemoglobin concentration indicates whether the red blood cells, depending on their size, contain little or a lot of hemoglobin, thus contributing to the identification of various conditions, including:
- Anemia ;
- Infections ;
- Inflammations ;
- Coagulation disorders ;
- Tumors .
In addition to the corpuscular indexes, to clarify the cause of a possible pathology, it is useful to consider the red blood cell count ( RBC ) and the erythrocyte volume distribution width ( RDW ).
Once the diagnosis has been established, the examination of MCHC and of the other corpuscular indexes allows to monitor the pathology and / or efficacy of treatments at regular intervals.
Normal values
Normally, MCHC is included in the reference range of 32-36% ; indicatively, the average value is 34%.
MCHC is automatically determined by the electronic cell counter, once hemoglobin and hematocrit have been measured.
The average cellular concentration of hemoglobin can also be calculated with the formula:
Hb (g / dl) x 100 / hematocrit value.
Note : the reference interval of the exam may vary slightly depending on age, sex and instrumentation used in the analysis laboratory. For this reason, it is preferable to consult the ranges listed directly on the report. It should also be remembered that the results of the analyzes must be assessed as a whole by the general practitioner who knows the patient's medical history.
MCHC High - Causes
What causes an increase in the value of MCHC?
A high MCHC is found essentially in hemolytic states, following the assumption of the spherocytic configuration of the red cells in some of these conditions; an example is hereditary spherocytosis and autoimmune hemolytic anemia .
Higher values of MCHC may also indicate the presence of hyperchromic cells (ie darker than normal), sickle cell anemia, hemoglobinopathy C (homozygosity for hemoglobin C), thyroid dysfunction, vitamin B12 and / or folic acid deficiency, disorders severe and liver disease .
Transitional causes of high MCHC can be:
- Pregnancy ;
- Dehydration .
MCHC Low - Causes
What are the causes of a low MCHC?
A lower-than-normal MCHC is typically found in hypochromic anemias (under the microscope, erythrocytes appear lighter, since the amount of hemoglobin is reduced).
The decrease in MCHC values can be observed in pathologies such as:
- Microcytic anemia ;
- Iron deficiency anemia (A. iron deficiency );
- Thalassemia (hereditary alteration of the blood that affects the chains that make up hemoglobin);
The reduction in the value of MCHC can also occur due to chronic diseases (eg rheumatoid arthritis, diabetes, infections and heart failure).
How to measure
MCHC: what is the exam?
To carry out the examination, the patient must undergo blood sampling from a vein in the arm or through a puncture of the finger or heel (newborns). Usually, MCHC's analysis is performed with automated tools .
Preparation
MCHC: is exam preparation required?
It is not necessary to be fasting to have a blood sample useful for the evaluation of the MCHC. The examination takes place, in fact, on the corpuscular part of the blood, that is on the cells, whose determination is not influenced by the fact of having taken food or drinks.
However, if in addition to the corpuscular indexes and the blood count, some other blood test must be carried out which foresees fasting (such as the determination of glycaemia or cholesterol) it will be necessary to abstain from ingesting food in the period preceding the withdrawal (of standard, 8-10 hours before). The general practitioner who prescribes the analyzes will still be able to provide useful information for each individual case.
Note. Some medications can affect MCHC values, especially the use of oral contraceptives and heparin. Therefore, before undergoing the exam, it is advisable to report any therapies in progress.
Interpretation of Results
MCHC is a corpuscular index that contributes to the evaluation of alterations affecting the blood.
- MCHC Low - The decrease in MCHC values ( hypochromia ) has been observed in pathologies such as iron deficiency anemia and thalassemia.
- MCHC Alto - An increased value of MCHC ( hyperchromia ) has been observed in pathologies in which hemoglobin is highly concentrated within red blood cells, such as autoimmune hemolytic anemia, burn patients and hereditary spherocytosis.
In general, the results reflect those relating to the mean corpuscular volume ( MCV ), meaning that the small red blood cells can have a lower value than MCHC.
It should be remembered that minimum deviations of the MCHC from the normal range may not correlate with any particular clinical significance; as for other hematological parameters, to establish a possible pathological association it is fundamental to interpret the results by referring to the general context .
Therefore, the MCHC values must be interpreted in relation to those relating to the hemoglobin dosage examination, always taking into consideration also the other erythrocyte indices (MCV and MCH).
