Mentzer index
Encyclopedia
The Mentzer index is used to differentiate iron deficiency anemia
from beta thalassemia. If a CBC indicates microcytic anemia
, these are two of the most likely causes, making it necessary to distinguish between them.
It is calculated from the results of a complete blood count
. If the quotient
of the mean corpuscular volume
divided by the red blood cell
count is less than 13, thalassemia is more likely. If the result is greater than 13, then iron-deficiency anemia is more likely.
It was described in 1973.
This test helps in differentiating iron deficiency from thalassemia. In iron deficiency, the marrow cannot produce as many RBCs and they are small (microcytic), so the RBC count will be low along with the MCV, and as a result, Mentzer's index is not as low, >13
Comparatively, in thalassemia, which is a disorder of globin synthesis, RBC production is preserved, but the cells are much small and fragile. So the RBC count is normal with a low MCV. Thus the Mentzer's index is <11.
It is also important to note that the test has a high specificity and low sensitivity. In a lot of cases, the index may fall in between 11 and 13, such cases a peripheral blood smear and iron studies would help to differentiate iron deficiency from thalassemia.
Iron deficiency anemia
Iron-deficiency anemia is a common anemia that occurs when iron loss occurs, and/or the dietary intake or absorption of iron is insufficient...
from beta thalassemia. If a CBC indicates microcytic anemia
Microcytic anemia
Microcytic anemia is a generic term for any type of anemia characterized by small red blood cells. The normal mean corpuscular volume is 76-100 fL, with smaller cells as macrocytic....
, these are two of the most likely causes, making it necessary to distinguish between them.
It is calculated from the results of a complete blood count
Complete blood count
A complete blood count , also known as full blood count or full blood exam or blood panel, is a test panel requested by a doctor or other medical professional that gives information about the cells in a patient's blood...
. If the quotient
Quotient
In mathematics, a quotient is the result of division. For example, when dividing 6 by 3, the quotient is 2, while 6 is called the dividend, and 3 the divisor. The quotient further is expressed as the number of times the divisor divides into the dividend e.g. The quotient of 6 and 2 is also 3.A...
of the mean corpuscular volume
Mean corpuscular volume
The mean corpuscular volume, or "mean cell volume" , is a measure of the average red blood cell size that is reported as part of a standard complete blood count....
divided by the red blood cell
Red blood cell
Red blood cells are the most common type of blood cell and the vertebrate organism's principal means of delivering oxygen to the body tissues via the blood flow through the circulatory system...
count is less than 13, thalassemia is more likely. If the result is greater than 13, then iron-deficiency anemia is more likely.
It was described in 1973.
This test helps in differentiating iron deficiency from thalassemia. In iron deficiency, the marrow cannot produce as many RBCs and they are small (microcytic), so the RBC count will be low along with the MCV, and as a result, Mentzer's index is not as low, >13
Comparatively, in thalassemia, which is a disorder of globin synthesis, RBC production is preserved, but the cells are much small and fragile. So the RBC count is normal with a low MCV. Thus the Mentzer's index is <11.
It is also important to note that the test has a high specificity and low sensitivity. In a lot of cases, the index may fall in between 11 and 13, such cases a peripheral blood smear and iron studies would help to differentiate iron deficiency from thalassemia.