Lab Values, part 17: Platelets

Hi, I'm Meris. And in this video, I'm going to be talking to you about the lab value of platelets. Let's go ahead and get started.

All right. So first up, let's just talk about what platelets are in the first place. Platelets are not actually a cell. They are cell fragments, and they are used in the body to help form clots. They are very important for helping to stop the bleed. And so this is happening all the time in your body. Whether you know it or not, you're getting little tiny micro injuries all the time, and platelets are showing up, and they're patching the bleed. They're saying, "No. No more. I'm covering this up. No blood gets out here, please." And they're also important when we have a really big bleed, right? If I have a big cut or some kind of rupture to an organ or something going on where I'm bleeding in a large way, my platelets have a very big and important function there too. So the expected range here is going to be that it's 150,000 to 400,000 per cubic millimeter. And remember that that is actually a measure of volume. So cubic millimeter is also 1 milliliter cubed. So in this case, we are talking about, again, a large number of cells in a small volume, but nowhere near the amount that we have of white blood cells, and certainly nowhere near the amount that we have of our red blood cells either. So we're talking about a smaller proportion. Platelets have a job in our body every second of the day, but not in the same way that red blood cells and white blood cells do. So there's a much smaller amount of them.

We do have a cool chicken hint here to help you remember the expected range, which is that I'm throwing a big party. I'm going to need like 150 to 400 plates to feed everyone. Plates, platelets. The reason this is 150 to 400 is because you will very commonly hear people abbreviate platelet counts. And most people aren't going to say, "He had a platelet count of 200,000." They're going to say, "200." And this is very common when we are dealing with these large numbers. We tend to truncate them and use the smaller numbers. So 150 to 400 plates is what I'm going to need for the party, 150,000 to 400,000 platelets.

Now, what if I have too few platelets in my blood? This is a condition we call thrombocytopenia, which means clot cell deficiency. So this is a deficiency of clotting cell in the blood. And in this case, we are talking about a platelet level that's less than 150,000 per cubic millimeter. Some possible causes here would be hemorrhage. If I'm bleeding, I'm going to use up platelets to try to stop the bleed. But also, as I'm bleeding, I'm bleeding whole blood out. So some platelets will be lost with that blood loss at baseline. So it will happen for two reasons. Now, leukemia is also a potential cause of thrombocytopenia. This might feel counterintuitive, but the reasoning here is because when I have leukemia, I have an overabundance. I have too many white blood cells, and they crowd out all the other cells. So I will end up seeing a deficiency in platelets for that reason. And then splenomegaly. If I have a large spleen that's going to town, just chew, chew, chewing things up, it might go a little bit overboard and chew up more platelets than it meant to, right? Or not necessarily that it meant to, that I need, leading to thrombocytopenia.

Now, what if I have the opposite condition? What if I have too many? If I have platelets greater than 400,000, we call this thrombocytosis. This is an overabundance of clotting cells. That's how that breaks down to those root words. Now, some causes here could be polycythemia. If I have a condition where I have too many cells in my blood, that's going to affect my platelets as well. Inflammatory diseases such as rheumatoid arthritis or inflammatory bowel disease, infection, cancer, and splenectomy. If you cut out my spleen, then it's not going to chew up all of those platelets very well or at all, right, and I'm going to end up with an elevated platelet count because they're not being broken down appropriately.

Now, the one thing that I really super duper want to call your attention to is if I have too few platelets, then my patient is going to be massively at risk for what? Bleeding. Because if I have a teeny, tiny little bleed, if I get a little cut or I brush my teeth and they start to ooze around the gum lines, I've got platelets. They're going to show up. They're going to help. They're going to patch that hole, stop the bleed. We're going to feel much better, right? No more issue there. But if I don't have enough platelets, I'm not going to effectively be able to stop that bleeding. So now I'm going to end up with that blood loss. So this is very important to educate your patients. If they have thrombocytopenia for some reason, you need to educate them about bleeding precautions, okay? Very, very big concern here is that I need to be looking out for signs of bleeding, things like oozing at the gum line, bruising of the skin, urine that has that red tinge to it, hematuria, or hematochezia, where we have blood in the stool. Anything like that. Anything that goes along with signs of bleeding is very important to report to the healthcare provider. And then you as the nurse should also be taking steps to minimize the risk for bleeding and educate your patients on how they can take those steps as well. If you want more information on that, check out our other videos about bleeding precautions.

All right. I'm so glad you stayed until the end because I'm going to test your knowledge of key facts provided in this video with some quiz questions.

The nurse educates a patient with thrombocytopenia to observe for signs of what possible complication?

Bleeding.

How should the nurse interpret a platelet level of 450,000 per cubic millimeter?

Thrombocytosis.

All right. That is it for this video. I really hope you learned something. Thanks so much and happy studying.