Hemoglobin and Blood Indices
Latha Rajendra Kumar MD
Hemoglobin
• Blood can carry very
little oxygen in solution.
• Hemoglobin is required
to carry oxygen around.
• Hemoglobin is found in
red blood cells
Hemoglobin
• In fact if the body had
to depend upon
dissolved oxygen in the
plasma to supply
oxygen to the cells –
• The heart would have
to pump 140 liters per
minute - instead of 4
liters per minute.
Hemoglobin
• Each red blood cell can
carry about one million
molecules of oxygen
• Hemoglobin is 97%
saturated when it
leaves the lungs
• Under resting
conditions is it about
75% saturated when it
returns.
Hemoglobin
• Hemoglobin is made from two similar proteins
that "stick together".
• Both proteins must be present for the
hemoglobin to pick up and release oxygen
normally.
• One of the component proteins is called
alpha, the other is beta.
Hemoglobin
• Blood cells are made up of two components.
• The hemoglobin is in solution inside the cell.
• The cell is surrounded by a membrane that
holds in the hemoglobin.
• A rough analogy would be a rubber water
balloon.
• The rubber would be the membrane, and the
water would be the hemoglobin
Porphyrin Ring
• At the core of the molecule
is porphyrin ring which
holds an iron atom.
• An iron containing
porphyrin is termed a
heme.
• This iron atom is the site of
oxygen binding.
• The name hemoglobin is
the concatenation of heme
and globin
Hemoglobin
• Hemoglobin is a remarkable molecular
machine that uses motion and small structural
changes to regulate its action.
• Oxygen binding at the four heme sites in
hemoglobin does not happen simultaneously.
• Once the first heme binds oxygen, it
introduces small changes in the structure of
the corresponding protein chain.
Hemoglobin
• These changes nudge the neighboring chains
into a different shape, making them bind
oxygen more easily.
• Thus, it is difficult to add the first oxygen
molecule, but binding the second, third and
fourth oxygen molecules gets progressively
easier and easier.
• This provides a great advantage in hemoglobin
function.
Hemoglobin
• When blood is in the lungs, where oxygen is
plentiful, oxygen easily binds to the first
subunit and then quickly fills up the remaining
ones.
• Then, as blood circulates through the body,
the oxygen level drops while that of carbon
dioxide increases.
Hemoglobin
• In this environment, hemoglobin releases its bound
oxygen. As soon as the first oxygen molecule drops
off, the protein starts changing its shape.
• This prompts the remaining three oxygens to be
quickly released.
• In this way, hemoglobin picks up the largest possible
load of oxygen in the lungs, and delivers all of it
where and when needed.
Hemoglobin Function
Hb must bind oxygen in lungs and release it in
capillaries
• When a first oxygen binds to Fe in heme of
Hb, the heme Fe is drawn into the plane of
the porphyrin ring
• This initiates a series of conformational
changes that are transmitted to adjacent
subunits
Hemoglobin Function
Hb must bind oxygen in lungs and release it in
capillaries
• Adjacent subunits' affinity for oxygen
increases
• This is called positive cooperativity
Hemoglobin
The heme group of one subunit, shown in the little
circular window, is kept in one place so that you can
see how the protein moves around it when oxygen
binds.
As it binds to the iron atom in the center of the heme,
it pulls a histidine amino acid upwards on the bottom
side of the heme.
This shifts the position of an entire alpha helix, This
motion is propagated throughout the protein chain
and on to the other chains, ultimately causing the
large rocking motion of the two subunits
Iron and Hemoglobin
• The mineral, iron, plays an
important role in the body’s
delivery and use of oxygen
to and by working muscles.
• It binds oxygen to
hemoglobin, which then
travels in the bloodstream
to locations throughout the
body.
Iron and Hemoglobin
• Generally, the more oxygen
there is being delivered, the
greater the body’s ability to
perform work.
• For this reason, iron
receives much attention for
its role in supporting
aerobic exercise, and it has
been postulated that a lack
of iron in the body can
reduce aerobic capacity and
impair endurance
performance.
Iron and Hemoglobin
• Iron deficient red blood
cells
• Low number or cells
• Note the hollow and
blanched appearance of
the red blood cells.
Sickle Cell anemia
• Sickle Cell Anemia is a
genetic disorder that is
characterized by the
formation of hard, sticky,
sickle-shaped red blood
cells, in contrast to the
biconcave-shaped red blood
cells (RBCs) found in
“normal” individuals.
• This disease is caused by a
mutation in hemoglobin.
Thalassemia
• It consists of two different
proteins, an alpha and a
beta.
• If the body doesn't produce
enough of either of these
two proteins, the red blood
cells do not form properly
and cannot carry sufficient
oxygen.
• The result is anemia that
begins in early childhood
and lasts throughout life.
Porphyria
• Porphyria is a group of
different disorders
caused by abnormalities
in the chemical steps
leading to the
production of heme
Porphyria
• It is characterized by extreme
sensitivity to light (exposure to
sunlight causes vesicular
erythema), reddish-brown urine,
reddish-brown teeth, and ulcers
which destroy cartilage and bone,
causing the deformation of the
nose, ears, and fingers. Mental
aberrations, such as hysteria,
manic-depressive psychosis, and
delirium, characterize this
condition as well.
Blood Indices and Anemia
Classification of anemia
•
Functional classification:
Hypoproliferative destruction (infective hematopoiesis).
• Clinical classification:
Causes of anemia (blood loss, IDA, hemolysis).
• Quantitative classification:
• Hematocrit
• Hemoglobin
• Blood cell indices (MCV, MCH, MCHC).
• Reticulocytes count.
Red cell indices
• MCV (mean corpuscular volume)
– The average volume of RBC
Hct
=
 10 (fl)
RBC count (m/µL)
e.g.
Hct= 40%
RBC=5.0 (m /µL)
MCV= 40/5.0  10 = 80 fl
NR= 80-96 fl
• MCH (mean corpuscular hemoglobin)
– The average content of Hb in average RBC.
– It is directly proportional to the amount of Hb and
RBC size.
MCH =
Hb
 10 (pg)
RBC count (m/µL)
e.g.
Hb = 14 g/dl
RBC = 4 (m/µL)
MCH= 14/4  10
= 35 pg
NR= 27-32 pg
• MCHC (mean corpuscular hemoglobin
concentration)
– Express the average concentration of hemoglobin
per unit volume of RBC.
– It defined as the ratio of the weight of hemoglobin
to volume of RBC.
Hb (g/dl)
MCHC=
 100 (%)
Hct (%)
e.g.
Hb = 14 g/dl
Hct = 45 %
MCHC 14/45  100 = 31%
NR= 32-36%
Symptoms of Anemia
Normal or High
Hemoglobin/Hematocrit
Check other
Causes of symptoms
e.g. Cardiac Pulmonary
Low
RBC indices
Serum iron and Total
Iron binding capacity of
Ferritin
Low Iron
IDA, chronic
diseases, Renal
diseases
MCV > 98
MCV=80-96
MCV < 80
MCHC < 32
History of acute blood loss
Auto immune Hemolytic anemia
Anemia of chronic Diseases
Anemia of infection
Normal
High Iron
Low B12
Hb
electrophoresis
for Thala.
BM exam
For
Sideroblastic
anemia
PA, GI
problems
Severe
malnutrition.
B12 and folate
levels
Low folate
High or Normal
Folate
malnutrition
GI problems
Liver disease
MPD
Liver Disease
Normal red cell morphology
Hypochromic
Hyperchromic
Macrocytic
Microcytic
IDA
Poikiolocytosis
Ovalocyte
Target cells
Stomatocytes
Sickle cells
Acanthocytes
Spherocytes
Nucleated RBC