2. Hemoglobin
Red blood cells
have hemoglobin
which carries oxygen.
Cells with MORE hemoglobin can carry more oxygen than those with
less hemoglobin.
Bigger cells tend to have more hemoglobin than small ones, and can
carry more oxygen.
3. Hb = Hemoglobin is the concentration of Hb in whole blood.
Hematocrit (Hct) is percentage of red blood cells in a volume of blood. Normal is about
40 - 50% for men, and 37 - 44% for women. Hct is about 3x the Hb.
Hct is easy to measure with a centrifuge and a ruler.
Anemia means that the hemoglobin and/or the hematocrit is less than normal.
Hemoglobin (Hb) is a protein inside of red
blood cells that contains iron that collects
oxygen from the lungs and carries it around in
the blood and delivers it to tissues. It also
collects carbon dioxide from the tissues and
delivers it back to the lungs to be exhaled.
Normal Hb is 13.5 - 17.5 g/dl for men and 12 -
15.5 g/dl for women.
4. Blood cells (erythrocytes) are made in the
bone-marrow and the process is called
erythropoiesis. There are cells called a
myeloid progenitor cells and they become
reticulocytes.
5. Reticulocytes are the immature red blood cells. They are larger than mature
red blood cells (RBCs) and mature over the following 2-3 days. It is normal
to have about 0.5% - 2.5% of the RBCs as reticulocytes.
If there are lots of reticulocytes in the blood it means that the bone marrow
is pushing them out early because they are needed for some reason.
RBCs live for about 120 days and then they are removed from our blood by
the spleen and liver and their components reused.
6. MCV - (mean corpuscular volume) is a
measurement of the volume (or size) of
the RBCs. Normal is 80 - 96 fL
Microcytic = small RBCs and can
happen if there isn’t enough iron to allow
them to fully grow.
Cells can become microcytic if:
● there is a chronic inflammatory or infectious process going on (causing stress on the
system, inability of the cells to fully use iron, and decreasing the life span of the RBC).
● there is something genetically wrong with the formation of RBCs (such as if there isn’t
enough hemoglobin being made as in Thalassemia)
7. ANEMIA + MCV normal = Normocytic (normal sized
RBCs) 80-100 fl
● This can happen in rapid blood loss.
● If the RBCs are being destroyed in the body
(hemolysis)
● This can happen if the bone marrow isn’t making
enough RBCs.
ANEMIA + Macrocytic (high MCV) >100 fl -
● Can happen when there is a vitamin B12 or folate
deficiency due to defective DNA synthesis.
● Can also occur in chronic liver disease and alcohol
use.
8. So the MCHC can tell you information about the
Hb content in relation to the volume of a cell
(not just how much).
RDW - red blood cell distribution width.
Normal is 11 - 15%. This is the range of sizes of
the RBCs in a blood sample. We want the RBCs
to be all about the same size (that indicates they
are being formed and used normally). If there
are large ones it may indicate that there are lots
of reticulocytes (immature RBCs).
Mean Corpuscular Hemoglobin - is the amount of Hb in 1 RBC. (Hb per RBC) Normal is 25
- 34 pg/cell. Think of this as the COLOR (how RED a RBC is). Less Hb is less “red.”
Mean Corpuscular Hemoglobin Concentration (MCHC) - is the amount of Hb in a unit
volume of RBCs. (Hb amount per volume of RBCs). Normal = 31 - 36% g/dL. Can also think
of it as color but with the added information that this is happening in a volume of RBCs and
not just a single RBC.
9. Looking (again) at the blood count and RBC indices:
Hemoglobin value (Hb) tells you the amount of hemoglobin in a sample of blood.
Hematocrit tell you how many RBCs are in a volume of blood (so it kinda tells you how much hemoglobin is in
the blood).
MCV tells you how big or small the RBCs are.
MCH - takes the weight of hemoglobin (measured) and divides it by the number of RBCs to give you an idea
about how much Hb is in each RBC
MCHC tells you concentration of the Hb in the RBCs (it takes volume or size of the RBCs into consideration)
13. Summary
Low Hb or Hct means there is anemia because there is just not enough hemoglobin
or red blood cells. This can be because RBCs are being destroyed, or they are not
able to be formed. Maybe there isn’t enough iron, or maybe the bone-marrow isn’t
functioning correctly.
BIG red blood cells are immature. Immature cells in the system means that
“children” are being recruited to become soldiers. That means there is a problem (but
is also indicates that the bone marrow that creates the immature cells is working). This
is reflected in the amount of RETICULOCYTES and the RDW.
Red blood cells that are too pink (not red enough) means there isn’t enough
hemoglobin. That means there isn’t enough “materials” (like iron for instance) to
make enough hemoglobin.