3. Red Blood Cell (RBC) Indices
Red blood cell (RBC) indices measure
the size, shape, and quality of your
red blood cells.
Red blood cells, also known as
erythrocytes, carry oxygen from your
lungs to every cell in your body.
Your cells need oxygen to grow,
reproduce, and stay healthy.
4.
5.
6.
7. What are they used for?
Red blood cell (RBC) indices are part
of a complete blood count .
The results of RBC indices are used
to diagnose different types of anemia.
There are several types of anemia,
and each type has a different effect on
the size, shape and/or quality of red
blood cells
8. Following red blood cell
indices:
Mean corpuscular volume (MCV), which
measures the average size of your red blood cells
Mean corpuscular hemoglobin (MCH), which
measures the average amount of hemoglobin in a
single red blood cell. Hemoglobin in red blood
cells that carries oxygen.
Mean corpuscular hemoglobin concentration
(MCHC), which also measures hemoglobin in red
blood cells. In addition, it includes a calculation of
the size and volume of your red blood cells.
Red cell distribution width (RDW) which
measures differences in the volume and size of
your red blood cells.
9. Mean corpuscular volume (MCV)
If your red blood cells -
smaller than normal, microcytic
it may mean you have:
Iron deficiency anemia, thalassemia
If your red blood cells are larger than
normal, Macrocytic
it may mean you have:
vitamin B deficiency ,Liver disease
10. Mean corpuscular hemoglobin
(MCH)
If the amount of hemoglobin is lower
than normal,
it may mean you have:
Iron deficiency anemia
If the amount of hemoglobin is higher
than normal, it may mean you have:
High level of cholesterol in the blood,
vitamin B deficiency
11. Mean corpuscular hemoglobin
concentration (MCHC)
If the average amount of hemoglobin is
lower than normal it may mean you
have:
Iron deficiency anemia
Thalassemia
If the average amount of hemoglobin is
higher than normal, it may mean you
have:
Hemolytic anemia, a type of anemia that
happens when red blood cells are
broken up
Hereditary spherocytosis, a rare genetic
12. Samples used for
Hb estimation
Capillary blood from finger prick.
Intravenous sample It should be taken
in anticoagulated tubes preferably in
EDTA.
13. Normal Values of Hb
Men 13.0 to 16.0 g/dl
Women 11.0 to 15.0 g/dl
Infants 16.0 to 19.0 g/dl
Critical Values-
Less than 5gm/dl- Severe
Anemia More than 20 gm/dl-
Polycythemia.
14. METHODS FOR ESTIMATION
OF HAEMOGLOBIN
The measurement of HB
concentration in the blood is
known as
HEMOGLOBINOMETRY.
Methods-
Colorimetric method
Gasometric method.
Specific gravity method
Chemical method.
15. Colorimetric method:
Colorimetric method is based on
intensity of color developed on
addition of some substance to the
blood.
values are measured by comparing
with known standard.
Include the following:
A. Visual Methods
B. Photoelectric Methods
17. Commonly used methods
Sahli’s Method – A Color Based Method
Visual method.
Principle :
◦ Hb is converted into acid hematin with the
action of dilute hydrochloric acid (N/10 HCl).
◦ The acid hematin is brown in color and its
intensity is matched with a standard brown
glass comparator in a visual colorimeter
called Sahli’s colorimeter.
18. Equipment:
◦ Sahli’s Hemaglobinometer consisting of :
Graduated hemoglobin tube
Comparator box with a brown glass
standard
◦ Hb Pipette
◦ Stirrer
◦ Dropper (dropping pipette)
REAGENTS:
a. N/10 HCl b. Distilled Water
Sample:
EDTA anticoagulated venous blood.
Blood obtained by skin puncture
19. Sahli’s Method
Procedure
Fill Sahli’s Hb tube upto mark 2 with N/10 HCl.
Deliver 20 μl (0.02 ml) of blood from a Hb pipette
into it.Stir with a stirrer and wait for 10 minutes.
Add distilled water drop by drop and stir till color
matches with the comparator.
Take the reading of meniscus from graduated
tube in grams
20.
21.
22. ADVANTAGES:
◦ Simple bedside test no colorimeter is
required.
◦ Reagents and apparatus are cheap.
DISADVANTAGES
◦ There can be visual error.
◦ Carboxy, met and sulfhaemoglobins cannot
be converted to acid hematin.
◦ Comparator can fade over the years.
◦ Color appearing of acid hematin takes long
time and also fades quickly.
◦ Source of light (day light or artificial)
influences the color comparison.
23. Hemoglobin Color Scale
This is rapid, simple,
inexpensive and
reliable.
Procedure:
A drop of blood is placed
on strip of
chromatography paper
and the color developed
is matched visually
against the printed color
24. B. Photoelectric Method
Cyanmethemoglobin method:
This is method of choice for
estimation of Hb,
recommended by ICSH
(International committee for
standardisation in haematology) .
25. Principle – Blood is diluted in a solution
called drabkin’s fluid containing
Pot. Ferricyanide converts Hb to
methamoglobin.
Methamoglobin reacts with Pot. Cyanide to
form cyanmetHb.
All forms are converted except SULF-Hb.
26. Sample: Blood from Skin Puncture or
EDTA anti-coagulated blood
◦ Take 5 ml of Drabkin solution in two test
tubes each.
◦ Add 20 micro liter of blood and mix well
◦ Allow the tube to stand for at least 5 min.
or more.
◦ Read in Spectrometer at 540 nm.
28. Advantage-
Less error
all forms of hemoglobin estimated
except sulphaemoglobin.
Disadvantage-
Hyperbilirubinemia affect value.
Turbidity effect.
29. Specific Gravity Method
This method gives approximate value
of Hb.
Method
A drop of blood is allowed to fall in
copper If drop sinks within this time its
specific gravity is higher.
If it floats- specific gravity is low hence
low Hb.
• Normal specific gravity of blood ranges
from 1.048-1.066.