Red Blood Cell (RBC) Lab Values

All right guys, in this lesson we're going to talk about red blood cells.

First off, the first thing we need to know is that red blood cells are measured in millions.

The normal range for a male patient is 4.5 to 5.5 million cells per microliter. In females it's just slightly lower, measuring for to 4.9 million cells per microliter. One important thing that we need to know is that red blood cells make up a percentage of the actual total blood volume. We measure that in hematocrit, and we're going to cover that in another lesson. But the thing that you need to recognize is that the red blood cell value will actually fall or it'll increase depending on the total blood concentration. That'll make sense a little bit later in the lesson when we talk about situations where you have high red blood cells and low red blood cells. But just keep in mind that they actually make up a percentage of the total blood volume.

So let's talk about the patho of red blood cells. The first thing you need to know is that they're made in the bone marrow, and they're stimulated by a hormone called erythropoietin. We also call it EPO, and it's stimulated by the kidneys. So when there's a decrease in red blood cell production, the kidneys kick out EPO, and that tells the bone marrow to produce more red blood cells.

Red blood cells are also called erythrocytes, and the young red blood cells are called reticulocytes. Providers will look at reticulocytes in certain diseases to see if red blood cell production is actually occurring. They want to make sure that red blood cells are being produced like they should.

When we look at the function of red blood cells we want to remember that their responsibility is to carry oxygen and they do this with hemoglobin. There's another lesson specifically on hemoglobin so I want you to check that out. But what we're concerned with is that the red blood cell is responsible for carrying that hemoglobin and oxygen to all the tissues that need it, so that gas exchange can occur.

Now as you can see here, red blood cells have what we call a biconcave shape meaning that they are caved in on both sides. What that does is it allows the red blood cells to have a greater surface area so it can attach more oxygen molecules to it. The other thing it does with the shape as it allows for greater flexibility so they can get into those tiny capillaries throughout the entire body. Another really important thing about red blood cells that is that 2.4 million red blood cells are made at around each second so we'd go through a ton of these every day.

Now let's take a look at how this plays into our actual lab samples when we're getting blood from a patient so that we can send it off to the lab.

When you get your blood sample from your patients and you're going to submit the blood test to the lab for your red blood cells, you're going to use a lavender top tube, and has EDTA in it which keeps the blood from clotting. When you're dealing with red blood cells or a lavender top tube, you going to need to pay attention to your technique. If you get your blood sample from your patient, and you just slam the sample into the vial with a lot of pressure you can actually break down the red blood cells. This is called hemolysis. And when hemolysis occurs it can actually artificially decrease your red blood cell count. And that can affect a lot of different values for your patient, so be very careful when you're introducing your sample into your vacutainers.

Also be thinking about the size of the catheter, or the tubing, or the needles that you're using to get your samples from. If the needle or tubing is too small, it can actually cause breakdown of the red blood cells at that level and you're never going to get an accurate sample. So just make sure that your needles in your tubing is large enough so that you're not going to get any of that break down.

So what happens if are RBC values are too high or too low. Well let's look at elevated rbc's?

Now remember I said that your red blood cells are a percentage of your total blood volume. So if you have a patient that's dehydrated, that means they don't have enough water, and that means you're going to have decreased plasma levels, and the total percentage of your patient’s RBC counts are going to be a little bit higher. They're not going to be as high as a condition called polycythemia vera, which is a bone marrow cancer. And that causes a major overproduction of red blood cells. Typically your dehydration values or only going to be increased slightly over normal, so you have to look at your patient and addition to the RBC values. Remember you always want to pay attention to what your patient is actually doing, and compare that to what your blood values are. Now if we think about what red blood cells do, which is to carry oxygen, if we have a disease or a process that causes the body to think it's not getting enough oxygen, so potentially respiratory diseases like COPD or pulmonary fibrosis, the body's going to think that it needs to create more red blood cells, therefore you're going to have increased values of your rbc's.

Now what happens if your RBCs are too low? This indicates some form of anemia.There’s this condition called sickle-cell anemia, where the actual red blood cell changes shape. This is going to decrease the surface area, and it's also going to keep the red blood cells from actually transporting oxygen and having gas exchange and also keeps the red blood cells from free-flowing throughout the entire body like it should. Another condition that causes anemia is pregnancy and kidney disease. Remember the kidneys kick out EPO, and because the kidneys are damaged the EPO production doesn't occur there for you have a decreased red blood cell count.

Another time you're going see decreased rbc's is bone marrow damage like aplastic anemia. Basically what's happening is the bone marrow is just not creating red blood cells like it should.

Another time you're going to see decreased rbc's are when there is some sort of hemorrhage or blood loss, so something like trauma. Again, this is where you're going to go back and look at your patient and see what's going on with them, and then compare that to what the actual blood value is showing on the test results. Also if your patient is exhibiting some sort of blood loss, you're going to need to treat the blood loss by red blood cell transfusion.

For today's lesson with red blood cells we look at the lab values and how your red blood cells impact your oxygenation for your patients
So let's recap.

Red blood cells carry oxygen, and they do this because they attach hemoglobin to their surface area and that helps with a gas exchange.

Remember your red blood cells are flexible so that allows them to move in and out of the small vessels very easily. When you have conditions like sickle cell anemia, your patients lack the ability for those red blood cells to move in and out like they should.

Remember that your red blood cells are a percentage of your total blood volume. If you have increase red blood cell counts, you could have decreased plasma, which could indicate some sort of dehydration. But again look at your patient and see what's going on.

When you have elevated RBC,Your body is telling you that you need more oxygen therefore it increases rbc's, or you have an overproduction of those red blood cells.

And finally if your red blood cells are decreased, you need to look at is there a blood loss or is there a decrease in RBC production that's occurring somewhere else.

That's it for today's lesson on red blood cells. Make sure you check out all the resources attached to this lesson. Now, go out and be your best selves today. And, as always, happy nursing!!