Heyyy guys! This is doctor Joel. In this Video I'm gonna be talking
about the complete blood count or the "CBC, which is"
extremely common in your clinical rotations. You're gonna see this over and
over again. So I would have to give it a 5/5 on its
importance or its yield. I don't really have enough space in one
short video to talk about the entire CBC so I have broken this topic up into
smaller more manageable bite size pieces. In this first video I'm going to be
"talking about the white blood cells," and in the second video I'll be talking
"about red blood cells," and in the last video or the third video
I'll be talking about the platelets. And then I'll ask some questions based on
what we've learned to see how well you can interpret a CBC.
Okay?! Let's get started!
So of what is a CBC or a complete blood count? "Well, its a very commonly ordered"
lab or blood panel that gives us some good information about the cell
types in a patient's blood. And those cell types are divided into 3
"main types. White blood cells," "red blood cells, and platelets."
First up in our discussion is going to be the white blood cells.
And just in case you're brand-new to "labs, let me real quick read these columns"
so it makes a little more sense. In the first column is the cell type.
The second column is saying that we're looking at the blood of the patient verses
like "serum, or urine, or tissue, or something
like" that. That's the least how my lab reports
it. The third column is the value for that cell type. The fourth column
is giving me units. And the last column is my reference range or my normal range.
"So, that means that this first row" represents
the total white blood cells taken from the patient's blood.
There was 4.6 times ten to the third or in other words 4600
white blood cells per microliter and the normal range for total white blood cells in
the blood is between 4.6 thousand
up to 11.03 thousand cells per microliter.
"So that was the first row, what about the" next five rows?
"Well, these next five rows are individual" cell types or cell lines
and they are all white blood cells. You'll notice also that
the units are given as a percentage. "So, of the 4600 white blood cells,"
per microliter of blood there was 52.1 percent of those
4600 were neutrophils and 31.8 percent of those were lymphocytes and so on
and so on. And if you at all those percentages up
they should equal 100 percent or the total of 4600
white blood cells. Does that make sense? The first group
of white blood cells that we'll talk about are the neutrophils.
And the neutrophils along with he eosinophils and basophils together makeup the
polymorphonuclear cells. They have this name because if you look
at the nucleus in these cells. The nuclei are
multi-lobulated and what that means is that instead of having
"a consolidated circular nucleus the," at nuclei make little lobules or kind of
like globs connected together by what looks like string
but is actually just thin strands of nucleus.
The nucleus of a neutrophil has about 2 to 5
of these lobes or lobules neutrophils are by far the most
abundant type of white blood cell that we see in the
blood and they play a major part
in our reaction to acute inflammation. Most especially the
inflammation and as a result bacterial infection. In fact
the pus that you squeeze out an abscess
is mostly neutrophils. "So given that information, what do you"
think you might use neutrophil part of this CBC to diagnose?
Bacterial infections! Bacterial infections would cause the neutrophil count to
go up. And this is called neutrophilia. I've
heard some people call neutrocytosis as well but
that's not as common. What are some other things that could cause a neutrophilia?
How about acute stress or burns or leukemia that's a good one.
"Steroid use, rheumatoid arthritis." "Okay, those are a couple."
"Shifting gears a little bit, now what" kind of diagnoses do you think would go
along with a decreased neutrophil count also called
a neutropenia. How about a folate deficiency or
maybe vitamin b12 deficiency. "Aplastic anemia, chemotherapy,"
maybe they're taking medication like "chloramphenicol,"
or some the sulfonamides. Those would decrease it as well.
"Alright, so those are some good reasons" "for decreased value. However,"
"most the time, in my experience, I use" this mostly
checking for an increased value to help me check for an infection in the patient.
Okay I don't often look for a decrease in this value.
Mostly an increase. Okay next on our
list to talk about are the eosinophils. These cells are named eosinophils
because this stain very well with the dye eosin which is a red dye. And you can
see already from this picture that these
cells are slightly more red
than the picture ot the neutrophils above. Alright so
what are some things that might cause the eosinophil count to change
either up or down? Well you may see an increased count
or an eosinophilia in "in allergic reaction, like a food allergy"
"or a bee sting, to someone who is allergic" to bees. Things like that.
Also parasitic infections is a big one. eosinophils contribute to our
attack against parasites by surrounding the parasite and then releasing their
granules which have a lot of substances that are toxic to the
invading parasite. And there's a link if you click here you can
watch video that happens pretty cool. What else? What else might cause the eosinophilia?
Well you can't go wrong if you say leukemia because certain types of leukemias
could "definitely increase the eosinophil count,"
or any other white blood cell for that matter. Also you could think of
"polyarteritis nodosa, and some autoimmune" disorders.
What about eosinopenia or a decrease in eosinophils? Well that's
a little bit tricky. Just because with eosinophils and basophils
"technically, according to my lab at least," 0 percent is still within normal range.
So its a little bit difficult to define eosinopenia.
Or a basopenia. However if someone "really twists your arm, you could say"
maybe a nutritional deficiency could decrease eosinophils
or basophils or any other white blood cell for that matter.
Also excessive exposure to glucocorticoids could do it.
but again.. Little bit tricky.. Okay let's move on.
Now on to the last one of the polymorphonuclear cells.
"Or the granulocytes, and those are" the basophils. Basophils are named
basophils because the way the take up basic dyes.
In this case giving the cell a very blue color. If you see a basophil under a microscope
it's going to look a lot like a mast cell. But the function is going to be a little
bit different. Basophils participate in our allergic response
and give us some of the symptoms that we experience with an allergic reaction.
So what might be a cause basophilia? Allergies! Yes! Also
"chronic myelogenous leukemia, or some" other blood cancers
Like hodgkin's disease. Also oral contraceptive pills.
Alright so what about basopenia? "Well again I mentioned this for eosinophils,"
its a little bit difficult to measure a a decrease
when the lower limit of normal "is 0. But I suppose, if someone twists your"
"arm and you have to give an answer," "you could say a nutritional deficiency,"
or excessive glucocorticoid use. All right. Moving on.
Now on to monocytes. Monocytes are the largest of all the white
blood cells. That makes them a little bit easier to pick out on a
microscope slide. They can approach three times the
diameter of a red blood cell. "So a lot like neutrophils, monocytes are"
very useful little cells. However unlike neutrophils
monocytes play more of a role in the chronic inflammation or infection vice the
neutrophils which are have more of an acute-phase cell.
Almost half of them are stored in our spleen and are released
when an infection is sensed. They are very motile so they are able to get themselves
into the tissue
where the inflammation or infection is. They have three important jobs. They
phagocytose bacteria or foreign bodies. And digest it.
And then they are involved in the presentation of that antigen
to T cells to help the T cells do their job.
And lastly monocytes also produced cytokines which recruit other where blood cells
and also mediate the fight against the invading bacteria or against
the cause of the information. So given that "information,"
"a cause of monocytosis, which" means and elevated
level of monocytes may be a chronic inflammatory state.
Monocytes do ramp up during a stress response.
You'll also see a lot of them in Cushing's syndrome.
Some viral syndromes and sarcoidosis.. How monocytopenia? Well they would be
decreased in aplastic anemia "of course, because many cell lines would"
be decreased in a plastic anemia.. "AML, acute myeloid leukemia."
Excessive glucocorticoid use would decrease them.
And some myelotoxic drugs would also decrease them.
Okay? Moving on.. OK next onto lymphocytes. There are
"three main types lymphocytes. T-cells," "B cells, and natural killer cells. First"
up on the list are T cells. There are three main subtypes
of T-cells: helper T-cells cytotoxic t-cells and memory T cells. Basically the helper
T-cells do what they sound like they do. They help
other cells in the immune system "function, mature, and do their job. And they
do" this by the production of certain
cytokines. Now this isn't a histology lecture so I'm
not going to get into more details. Next up the cytotoxic t-cells
are used to help destroy infected cells and those are our
own body cells that are infected with viruses.
And lastly memory t-cells which hang around for a long time and have the
ability to remember antigens so they can react faster
the next time were infected with that same pathogen.
OK? Next are B cells and there's two main types B cells that
I wanna talk about. "The plasma B cells, which produce large"
"amounts of antibodies, like little factories, to help"
us fight infections and again memory B cells which hang
around for a long time just like the T- memory cells and they have the ability a
lot like the memory t-cells to remember the antigens
of specific infections to help speed up our response the next time we're infected with
that pathogen. And lastly natural killer cells. They are not the
same as cytotoxic t-cells. But they play a similar role by helping
us to kill infected cells "or cancer cells. So, that being said,"
what could be a cause of lymphocytosis?
How about viral infections.. Perfect right? Do you remember which type of white
blood cells respond initially to bacterial infection?
Well that would be neutrophils. Lymphocytes are more geared toward protecting us
against viral infections. So in a viral infection you would expect
that to go up. What else? Leukemia.
This is pretty obvious right? This is pretty much a reason for an increased
number of most or all of the previous white blood
cells we've talked about. And adrenal insufficiency can be a cause
of lymphocytosis. What about lymphocytopenia? Well here's
a good one.. "HIV, this virus destroys"
"T-cells, specifically the cd4 t-cells." So this could be an early indicator
along with a physical exam and a history that could point you towards doing more
specific tests for HIV in a patient. Alright?
Next up aplastic anemia. That would decrease
a lot of cells. Glucocorticoid use again. Systemic lupus erythematosus.
And rheumatoid arthritis. Cool? Let's move on!
"Thanks for watching guys! Hey look, if" you're trying to find the next video or
part two of the CBC little mini lecture-series then just click on the link here on the
screen. It will take you right to it. "Also if this video is helpful at all, gimme"
"a ""like"", subscribe. Also leave me a comment." I love comments
I'm always trying to improve videos I'm always try to look for what you need
to help you through school. Okay? GOOD LUCK!