A presentation on RBC indices and their role in differential diagnosis of different types of anemias, presented by M. Mohsin, Ahsan Iqbal, Basit Ali, Muhammad Ali and Irfan Kaleem from 1st Year MBBS.

2. Presented
by:
1. Muhammad
Mohsin Ali
Dynamo
2. Ahsan Iqbal
3. Muhammad
Basit
4. Muhammad Ali
5. Irfan Kaleem

4. Complete Blood Count (CBC)
It includes:
 White blood cell (WBC, leukocyte) count
 White blood cell types (WBC differential)
 Red blood cell (RBC) count
 Hematocrit (HCT, packed cell volume, PCV)
 Hemoglobin (Hgb)
 Red blood cell indices
Mean Corpuscular Volume
Mean Corpuscular Hemoglobin
Mean Corpuscular Hemoglobin
Concentration
 Platelet (thrombocyte) count
 Mean platelet volume (MPV)
 Red Blood Cell Distribution Width (RDW)

5. So what are Red Blood Cells Indices?
An index is a quantitative measurement of anything. Therefore a
Red Blood Cell Index would mean a quantitative measurement
of Red Blood Cells, the amount and the concentration of
Hemoglobin in them.
Red Blood Cell Indices include:
1. Mean Corpuscular Volume (MCV)
2. Mean Corpuscular Hemoglobin (MCH)
3. Mean Corpuscular Hemoglobin Concentration (MCHC)
They were first introduced by Wintrobe in 1929 to define the size
(MCV) and hemoglobin content (MCH, MCHC) of red blood cells.
Red cell indices can be calculated if the values of hemoglobin,
hematocrit (packed cell volume), and red blood cell count are
known.

6. MEAN CORPUSCULAR VOLUME (MCV)
 It is the measure of average size or volume of RBCs.
 Expressed in femtoliters (fl; 10^-15 liter) or as cubic microns (μm ).
 Normal Value: 87± 7 fl (80-100 fl)
 Calculated by:
 Normal MCV—Normocyte
 High MCV—Macrocyte (Pernicious and megaloblastic anemia)
 Low MCV—Microcyte (Iron deficiency anemia)

7. MCV VALUES AND
DIFFERENT
TYPES OF
ANEMIA

9. MEAN CORPUSCULAR HEMOGLOBIN
(MCH)
MCH quantifies the amount or weight of hemoglobin per
RBC.
Measured in picograms (pg)
Normal Value: 29 ± 2 picograms (pg) per cell.
Calculated by:

10. MEAN CORPUSCULAR HEMOGLOBIN
CONCENTRATION (MCHC)
MCHC indicates the amount of hemoglobin per unit
volume.
In contrast to MCH, MCHC correlates the hemoglobin
content with the volume of the cell.
Expressed as g/dl of red blood cells or as a percentage
value.
Normal values: 34 ± 2 g/dl.
Calculated by

12. RBC Distribution Width (RDW)
o Coefficient of variation in size distribution of RBCs
o Displayed as a percentage
o Normal value: 1 3 ± 1 .5%.
o Usual size of RBC is 6-8 µm
o Measured as : RDW = (Standard deviation of MCV
÷ mean MCV) × 100
o Normal Value: Heterozygous Thalassemia (in case
of anemia)
o Increased Value: Anisocystosis (RBCs of unequal
sizes)

13. Practically Determining Blood Indices
Peripheral Blood Smear: A blood film or peripheral blood smear is a
thin layer of blood smeared on a microscope slide and then stained in
such a way to allow the various blood cells to be examined
microscopically.
 Examination of a blood film stained with Wright’s stain provides
information about various types of anemias.
 RBCs are 7-8 µm in diameter
 Peripheral concentration of Hb, central pallor.
 Used to determine type of anemia that is present in the patient.
 For instance, the occurrence of hypochromic, microcytic RBCs
indicates iron deficiency anemia, that may occur due to chronic
blood loss.
 The presence of macrocytes is often found in patients of
megaloblastic anemia due to deficiency of Vitamin B-12 and Folic
acid.

14. Automated Hematology Analyzers:
 A Beckman Coulter counter, using electrical analysis
based on Coulter’s principle, is used to perform CBC.
 In this process, a suspension of blood cells is passed
through a small orifice or aperture simultaneously with
an electrical current.
 This is known as the sensing zone.
 In this zone, each particle displaces its own volume of
electrolyte.
 The counter measures this volume change as a pulse,
with the height of each pulse being proportional to the
volume of the particle.
 From this Automated Analyzer, we get the values of RBC
indices, which can be interpreted for different kinds of
anemias:

15. ANEMIA
Anemia means deficiency of hemoglobin in the blood, which can be caused
by either too few red blood cells or too little hemoglobin in the cells.
Types of Anemia
1. Morphologically Classified
2. Etiologically Classified

18. 1. Normocytic Normochromic:
The MCV and MCHC values of RBCs are normal. But the number of
RBCs are less.
2. Macrocytic Hypochromic:
The MCV values are large. The MCHC values are low. Therefore the
RBCs appear to be of large size with pale coloration.
3. Macrocytic Normochromic:
The MCV values are again large. However, the MCHC values are
normal, so that the RBCs appear large with normal coloration.
4. Microcytic Hypochromic:
The MCV values are less. The MCHC values are also less. As a
consequence, the RBCs appear smaller with pale coloration (central
pallor is more than 50% of diameter; normally it is 30-40%).
There are NO hyperchromic anemias. In spherocytosis, the MCHC
is increased due to loss of membrane and the consequent spherical
shape assumed by the cell.

19. Normocytic Normochromic
Macrocytic
Normochromic
Microcytic
Hypochromic
Macrocytic
Hypochromic

20. But these were the characteristics of RBCS as they occur in different
types of anemias! What are the common types of anemias that show
these characteristics?

21. Why we need to assess Anemias based on red blood cell
indices?
Suppose a patient, after undergoing a CBC, comes to a clinician, with the
results of MCV, MCHC and MHC as under:
We evaluate him as being Microcytic and Hypochromic.
Now we wish to identify the cause to administer proper treatment. This is
done by carefully planning the clinical causes and morphological
characteristics of anemias, as we will be doing next.
RBC index Value Normal Value
MCV 70 fl 80-100 fl
MCH 20 pg 27-31 pg
MCHC 28 g/dl 30-36 g/dl

23. Type of Anemia Cause Morphological
Characteristics of RBCS
Red Blood Cell Indices
Hemorrhagic
Anemia
Acute Blood Loss—after
accident
Chronic Blood Loss—due
to peptic ulcer,
hemophilia, prolonged
external and internal
bleeding
Normocytic, Normochromic
Microcytic, Hypochromic
(due to iron deficiency)
MCV, MCHC: within normal range
MCV and MCHC less than normal
Hemolytic Anemia
(destruction of
RBCS)
Extrinsic (due to external
factors)
1. Liver Failure
2. Renal disorder
3. Hyperspleenism
4. Burns
5. Infections (hepatitis,
malaria)
6. Drugs (penicillin)
7. Lead Poisoning
Intrinsic (abnormal RBC
shape)
1. Sickle Cell Anemia
2. Thalassemia
Normocytic Normochromic
Sickle Shape, normocytic
Microcytic, Hypochromic
MCV and MCHC values within normal range
MCV values are normal
MCV and MCHC values are less

24. Aplastic Anemia Bone marrow aplasia
due to
i. Radiation
ii. Toxic Chemicals
iii. Autoimmune
disorders ()
iv. Unknown cause
(idiopathic)
Normocytic,
normochromic
MCV and MCHC normal, RBC count less
Anemia of Chronic
Diseases
a. Noninfectious
inflammatory
diseases—
rheumatoid arthritis
b. Chronic infections
c. Chronic Renal
failure
d. Neoplastic
disorders—
Microcytic, normochromic Decreased MCV, MCHC normal
Nutrition Deficiency
Anemia (due to
deficiency of
substance
necessary for
erythropoiesis)
Iron Deficiency
Vitamin B-12
(Pernicious Anemia)
Folic Acid
(Megaloblastic anemia)
Microcytic, hypochromic
Macrocytic, hypochromic
Macrocytic,
normochromic
MCV and MCHC less
MCV more, MCHC less
MCV more, MCHC less
MCV more, MCHC within normal range

28. 1. N Engl J Med
2005;352:1011-23
2. Guyton and Hall, Textbook
of Medical Physiology
3. Sembulingam, Essentials of
Medical Physiology
4. Walker et al, Clinical
Methods: The History ,
Physical, and Laboratory
Examinations.
5. Perkins S., Diagnosis of
Anemia