Hema 2 Lab – Lesson 1 – RBC Indices
We know that RBC indices are used in clinical setting in order to assess the degree of anemia through blood
picture. So, through obtaining RBC indices or through measuring the RBC indices, we will have an
information about the morphology of our RBCs.
There are 3 indices:
1. Mean Cell Volume
It is the measure on the average volume of RBC in a given blood sample
Related to the size of the RBC
→ In other words, if the MCV is higher, therefore we are going to expect bigger RBCs when we
are going to examine the blood sample under a microscope
→ If the MCV is low, of course, that means that the RBCs are small
2. Mean Cell Hemoglobin
A measure on the average content (weight) of hemoglobin in a single RBC
Related to the color of RBCs when examined under the microscope
3. Mean Cell Hemoglobin Concentration
Average concentration of hemoglobin in a unit volume of RBCs in a sample
Related to the color of the RBCs when examined under the microscope
What is the difference between an MCH and MCHC?
The main difference between the two is that MCH is a measure of hemoglobin content in a single
RBC, whereas the MCHC is a measure of hemoglobin concentration in a given population of RBCs.
The MCHC considers the amount of hemoglobin concentration in a given volume or in a given
population of RBCs; whereas in the MCH, it is a measure of hemoglobin content in a single RBC
only.
Both MCH and MCHC are related to the color of the RBCs because our hemoglobin is the one
responsible to give red color to our RBCs
If there is low MCH or low MCHC we can expect that the RBC has a bigger central pallor when
seen under the microscope
→ What does this mean? Remember when we are going to observe our RBC under the microscope,
we can observe an RBC with a central pallor and that is the normal appearance of our RBCs
under the microscope. The central pallor occupies about one-third (1/3) of the volume of the
RBC cytoplasm and the rest of the cytoplasm is already red in color because the rest of the
cytoplasm is filled with hemoglobin.
→ However, if the hemoglobin is low, if the RBC contains a low amount of hemoglobin, then we are
going to expect that the RBC will have a bigger central pallor and the only little portion will be
filled with hemoglobin. So, the paleness there indicates the absence of hemoglobin in the inner
area and the hemoglobin is only found on the edge part.
→ If there will be a bigger central pallor that means that the RBC contains less amount of
hemoglobin.
, In an automated analyzer, the MCV is directly measured; whereas the MCH and MCHC are all
calculated.
REVIEW on how MCV is measured in an automated analyzer:
RBCs are measured by the principle of electronic impedance. If you remember, an automated analyzer is
equipped with electrodes, there is an internal electrode and external electrode, and between these
electrodes there is an electrical current.
This electrode or electrical current is present in the solution where our RBCs are being measured. Now,
our RBCs pass through a sensing zone. As they pass through the sensing zone, the RBCs will pass
through these electrical current, but our RBCs do not conduct electricity, but they rather resist an
electrical current. So, when RBCs pass through this electrical current, there will be a resistance created
and that resistance will be generated in terms of a pulse, there will be a pulse voltage generated and that
generated pulse voltage is equivalent to the volume of the RBC. The higher the pulse generated, the
bigger or the higher the volume of the RBC. That is why in an automated analyzer the MCV is directly
measured; whereas the MCH and MCHC are all calculated.
But as for manual calculation, we can obtain MCV using this formula:
Hematocrit is expressed as percentage (%) or liter by liter (L/L) conventional unit
→ Ex: 45% or 0.45 L/L
→ Note: In the computation for MCV, you must use the percentage – you must convert the
conventional unit to S.I. unit
RBC count is expressed as times 10 to the 12 per liter
These are both in S.I. unit
Unit: fL or femtoliter
Hemoglobin is expressed as grams per dL (SI unit) or grams per Liter (conventional unit)
→ Ex: 190 g/L → SI = 19 g/dL (divide the conventional unit by 10 in order to obtain the SI unit)
RBC count is expressed as times 10 to the 12 per liter
→ Ex: 4.5 x 1012/L – only use the whole number, discard the scientific notation
Unit: pg or picogram
Hemoglobin is expressed as grams per dL (SI unit)
Hematocrit is expressed as percentage (%)
Unit: g/dL or percentage (%)
We know that RBC indices are used in clinical setting in order to assess the degree of anemia through blood
picture. So, through obtaining RBC indices or through measuring the RBC indices, we will have an
information about the morphology of our RBCs.
There are 3 indices:
1. Mean Cell Volume
It is the measure on the average volume of RBC in a given blood sample
Related to the size of the RBC
→ In other words, if the MCV is higher, therefore we are going to expect bigger RBCs when we
are going to examine the blood sample under a microscope
→ If the MCV is low, of course, that means that the RBCs are small
2. Mean Cell Hemoglobin
A measure on the average content (weight) of hemoglobin in a single RBC
Related to the color of RBCs when examined under the microscope
3. Mean Cell Hemoglobin Concentration
Average concentration of hemoglobin in a unit volume of RBCs in a sample
Related to the color of the RBCs when examined under the microscope
What is the difference between an MCH and MCHC?
The main difference between the two is that MCH is a measure of hemoglobin content in a single
RBC, whereas the MCHC is a measure of hemoglobin concentration in a given population of RBCs.
The MCHC considers the amount of hemoglobin concentration in a given volume or in a given
population of RBCs; whereas in the MCH, it is a measure of hemoglobin content in a single RBC
only.
Both MCH and MCHC are related to the color of the RBCs because our hemoglobin is the one
responsible to give red color to our RBCs
If there is low MCH or low MCHC we can expect that the RBC has a bigger central pallor when
seen under the microscope
→ What does this mean? Remember when we are going to observe our RBC under the microscope,
we can observe an RBC with a central pallor and that is the normal appearance of our RBCs
under the microscope. The central pallor occupies about one-third (1/3) of the volume of the
RBC cytoplasm and the rest of the cytoplasm is already red in color because the rest of the
cytoplasm is filled with hemoglobin.
→ However, if the hemoglobin is low, if the RBC contains a low amount of hemoglobin, then we are
going to expect that the RBC will have a bigger central pallor and the only little portion will be
filled with hemoglobin. So, the paleness there indicates the absence of hemoglobin in the inner
area and the hemoglobin is only found on the edge part.
→ If there will be a bigger central pallor that means that the RBC contains less amount of
hemoglobin.
, In an automated analyzer, the MCV is directly measured; whereas the MCH and MCHC are all
calculated.
REVIEW on how MCV is measured in an automated analyzer:
RBCs are measured by the principle of electronic impedance. If you remember, an automated analyzer is
equipped with electrodes, there is an internal electrode and external electrode, and between these
electrodes there is an electrical current.
This electrode or electrical current is present in the solution where our RBCs are being measured. Now,
our RBCs pass through a sensing zone. As they pass through the sensing zone, the RBCs will pass
through these electrical current, but our RBCs do not conduct electricity, but they rather resist an
electrical current. So, when RBCs pass through this electrical current, there will be a resistance created
and that resistance will be generated in terms of a pulse, there will be a pulse voltage generated and that
generated pulse voltage is equivalent to the volume of the RBC. The higher the pulse generated, the
bigger or the higher the volume of the RBC. That is why in an automated analyzer the MCV is directly
measured; whereas the MCH and MCHC are all calculated.
But as for manual calculation, we can obtain MCV using this formula:
Hematocrit is expressed as percentage (%) or liter by liter (L/L) conventional unit
→ Ex: 45% or 0.45 L/L
→ Note: In the computation for MCV, you must use the percentage – you must convert the
conventional unit to S.I. unit
RBC count is expressed as times 10 to the 12 per liter
These are both in S.I. unit
Unit: fL or femtoliter
Hemoglobin is expressed as grams per dL (SI unit) or grams per Liter (conventional unit)
→ Ex: 190 g/L → SI = 19 g/dL (divide the conventional unit by 10 in order to obtain the SI unit)
RBC count is expressed as times 10 to the 12 per liter
→ Ex: 4.5 x 1012/L – only use the whole number, discard the scientific notation
Unit: pg or picogram
Hemoglobin is expressed as grams per dL (SI unit)
Hematocrit is expressed as percentage (%)
Unit: g/dL or percentage (%)
