Mentzer index more than 13 suggests a
diagnosis of
a) Iron deficiency anemia
b) Thalassemia
c) Hereditary Spherocytosis
d) Autoimmune Hemolytic Anemia
Correct Answer - A
Ans. is ‘a’ i.e., Iron deficiency Anemia
Mentzer index more than 13 suggests a diagnosis of Iron-deficiency
anemia.
Mentzer index
The Mentzer index is used to help in differentiating iron deficiency
anemia from beta thalassemia.
The index is calculated as the quotient of the mean corpuscular
volume (MCV, in fL) divided by the red blood cell count (RBC, in
millions per microleter).
If the Mentzer index is less than 13, thallassemia is said to be more
likely.
If the Mentzer Index is greater than 13, Then iron-deficiency anemia
is said to be more likely.
Principle
In iron deficiency, the marrow cannot produce as many RBCs and
they are small (imcrocytic), so the RBC count and the MCV will both
be low, and as a result, the index will be greater than 13.
Conversely, in thalassemia, which is a disorder of globin synthesis,
the number of RBCs produced is normal, but the cells are smaller
and more fragile. Therefore, the RBC count is normal, but the MCV
is low, so the index will be less than 13.
n practice, the Mentzer index is not a reliable indicator and should
not, by itself be used to differentiate the two conditions.
Index Formula
Value for
iron
deficiency
anemia
Value for
iron
thalassemia
Mentzer
index
MC V/RBC
count > 13 < 13
Shine and
Lal index
MCV2 x
MCH x 0.01 > 1530 < 1530
England and
Fraser index
MCV – RBC
- (5 x Hb)
5.19
0 < 0
Srivastava
index MCH/RBC > 3.8 < 3.8
Green and
king index
MCV2 x
RDW x
Hb/100
65 < 65
Red cell
distribution
width index
MCV x
RDW/RBC > 220 < 220