Platelets (PLT) Lab Values

In this lesson we're going to talk about platelets and how they play a role in your patient's ability to clot.

The normal values for platelets are going to be a hundred thousand to 400,000 cells per microliter. Anything less than a hundred thousand cells per microliter is considered to be a condition called thrombocytopenia. Platelets are also called thrombocytes, so that's where we get the word from beside of penia meaning low platelets.

In this picture you can see that the thrombocyte, this yellow cell is much smaller than red blood cells or white blood cells.

Let's look at how platelets work.

Platelets are formed from the cells called megakaryocytes, and they're these really large cells, and they break off all of the little platelets. I'm megakaryocytes can actually produce anywhere from 1000 to 3000 platelets during its lifetime. These are all derived from the bone marrow.

Now the way platelets work is that you'll have an injury at a particular site, so maybe a laceration. What happens is the collagen in the skin triggers a reaction that stimulates platelets to come to the site. Normally platelets are these little round flat cells, and when they're triggered they actually activate and create these little finger-like projections. Think of them as like sticky fingers. That makes them more likely to stick to whatever site they’re going to. The entire clotting Cascade is very very complicated, and there are a lot of other factors that play into it, but what you need to know is that the platelets arrive to the site and stick to the injury, and that triggers more of an active response and it brings in all these other platelets and as you can see in this picture, the platelets all start to form this little clot. The platelets will also interact with fibrin to create a clot at the site and that's what stops the bleeding.

So what do you need to be considerate of whenever you're drawing a sample? Just know that you're platelet samples are going to be submitted in a lavender top tube, that has the EDTA in it. It's often submitted with the CBC, and that helps to give a general overview of all the cells in your patient. So you also get results that'll include things like yours white blood cells, red blood cells, hematocrit and hemoglobin.

The next question you probably have is what do high and low values of platelets indicate?

With elevated platelets, a condition known as thrombocytosis, is when the platelets are greater than 400000 cells per microliter. Conditions that will trigger this are things like cancers or malignancy. Another situation is the absence of a spleen. The spleen's responsibility is to break down old or damaged platelets, and if there's no spleen, that can't occur and therefore your platelet values may go up. Certain types of birth control can also cause increase in platelets, and also the condition that we talked about in some other lessons called polycythemia vera. Polycythemia vera is in uncommon type of bone marrow cancer causes this massive overproduction of cells. These will include white blood cells, red blood cells and platelets. Treatment is typically bloodletting, or the actual removal of blood from a patient through phlebotomy to decrease the overall blood volume. The blood becomes really thick and viscous when there's as overproduction of cells, and that's how they treated. It can also be treated through making sure the patient is adequately hydrated, and some medications can help this condition.

If a platelet values are low it's a condition called thrombocytopenia. There are a couple of specific conditions, one called ITP. This is idiopathic thrombocytopenia purpura, and what it is is it's an autoimmune disease that attacks antibodies on the platelets and destroys them. If you don't have platelets, you can't clot, so these patients are at a much higher risk of clotting. Patients that have ITP will go through some sort of medication therapy that suppresses the immune system so that it doesn't attack itself. These patients are definite risk for bleeding, and sometimes they’ll develop these little areas of bleeding underneath the skin called petechiae. Sometimes they look like little bleeding stars. So if you see that, you might want to suspect a platelet issue with your patient. Another condition that you're going to see decreased platelets in is hemorrhage and you're going to treat those patients with platelet transfusions. Patients that are undergoing chemotherapy or radiation for leukemia they also have decreased platelets. And another thing to consider is medications. Certain medications can have the potential to decrease platelet production. These are things like diuretics, NSAIDs, Ranitidine, and certain types of antibiotics. So be sure to review any medications if you're suspicious of some sort of clotting issue for your patient.

Nursing concepts for this lesson include a lot of values and clotting, because that's what the responsibilities of the platelets are.
So let's recap.

The normal values for platelets are 100,000 to 400000 cells per microliter.

The responsibility of the platelet is for clotting.

If you have increased platelets, that could be from cancers, polycythemia vera, or over production. Also consider if the patient has had a splenectomy.

Decrease platelets are on much more concerning, so consider things like ITP, leukemia, or Hemorrhage.

If your patient does have decreased the values of platelets, or are at risk for having decrease platelets, make sure that they understand that they are always at risk for bleeding. Make sure that they know when to come to the emergency room if they have some sort of injury that won't stop bleeding, and make sure that you go over any medications that could potentially cause bleeding issues.

That's it for our lesson on platelets. 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!!