Lab Values, part 1: Lab Panels - CBC, BMP, Liver Function

Hi, I am Meris, and in this video, I am going to be talking to you about some different laboratory panels, including a complete blood count with and without differential, basic metabolic panel, and liver function panel. I am going to be following along using our lab values flashcards. These are available on our website, leveluprn.com, if you want to grab a set for yourself. Or if you are more of a fan of digital products, I would invite you to check out Flashables, which is the digital version of all of our flashcards available on demand at your fingertips at all times. All right. Let us go ahead and get started.

Now, first up, I want to talk to you about the different lab panels that you may encounter in your clinical practice because it is really important for you to understand, what does this test mean? What are the components of this panel? What kind of information might I be able to glean from it? And the reason this matters is because many times the feedback that I get from nurses is, "Well, it is not my job to know that. It is the provider's," and that is absolutely correct. It is the provider's job to know what tests are in which panel and when to order them and why. However, how am I possibly supposed to advocate for my patient or question an order if I do not know what the lab panels mean? So we are going to empower you with that information today so that you know when to advocate for a specific test for your patient, or just what the purpose is of the tests that are being run for your patients. So there is going to be two videos about this because I have broken it up into two sections, and I want to talk to you in depth about these, okay?

So first up, we are going to be talking about a complete blood count, also known as a CBC, and it is what it sounds like. It is counting the components of your blood. So the way that I think of this is this is looking at the formed elements, the things that can be counted by looking under a microscope, which is how this is done when it is done manually. A CBC is going to give me information about what is going on in a couple of different areas. We are going to get information about the red blood cells, and this will tell us both how many there are, but also, what size they are, what shape they are. Do they have a nucleus or not. It is going to give us information about that red blood cell, but for your purposes, I just want you to understand it is going to give us red blood cell information. It is also going to give us a little bit of white blood cell information, such as what is the total white blood count. So that can help us identify if we are experiencing an infection, but it does not give us any more information than that. And then it can also give us information about the hemoglobin, which again, is going to be a component of that red blood cell. However, we do separate that out because that is an important lab value for bleeding. For hemorrhage, any kind of concern that your patient might be bleeding, we are going to need to know what their hemoglobin is, and also their hematocrit.

Now, I want to just point out to you that sometimes these two values are referred to as an H&H, hemoglobin and hematocrit, and they can be run on their own as an H&H where it is just those two tests in that one panel. It is that same information, but it might be pared down. For instance, if we know for a fact we have somebody who is bleeding, and we want to see what their hemoglobin is looking like every four hours, I do not need a complete blood count, I am just looking at those two values, but that is going to be in that complete blood count as well, and information about the number of platelets. So by getting this complete blood count, we are able to say, "Here is the complete contents of the blood. Here is how many of the different cells, and what they look like," and how they are acting like in some cases, specifically talking about red blood cells.

Now, what if I think this patient has an infection? What if they come to me and they are complaining of symptoms that make me think of pneumonia or urinary tract infection or postoperative infection? Well, it is not enough for me to just know that they have an elevated white blood cell count, right? That is helpful information if their white blood cell comes back at, let us say, 20. Well, that tells me for sure we have got some kind of infection going on inside this person. We need to take a closer look. But I want to know, is this infection new? Is this a chronic infection? Is it kind of old, like has it been going on for a while? Is this due to allergy? Is this due to parasite? Well, we can figure that out by doing something called a differential.

So if you ever see a test ordered, a panel called CBC with diff, or with differential, or and differential, what this means is I want everything that is in the CDC, but I want you to take it one step further. I want you to differentiate. So tell me the difference between the white blood cells. I want you to tell me how many neutrophils are in there, right? How many monocytes, how many leukocytes, how many basophils, how many eosinophils, right? I want to know how many of each particular type of white blood cell is in my patient's blood at this moment, because that will give me a lot of information about the type, source, and longevity of the infection that they are experiencing. Now, that is CBC with and without differential.

I want to talk to you about the basic metabolic panel, or BMP, and I want you to notice that I really exaggerated that middle syllable there because we also do a test called a BNP, like Nancy, brain natriuretic peptide. It is very easy to get these confused, and again, this is why we do not use verbal orders as our standard. So a BMP, this is what sometimes you will hear facilities call a chemistry, and I like this term for it. I like it. I like both terms, actually, because it gives you some information. A chemistry or a metabolic panel, a basic metabolic panel, is going to give me information about what is happening at the chemical level. So it is not giving me any information about the cells or the formed elements of the blood. It is telling me what chemicals are making up this blood. So we have a lot of stuff that is going to be included in the BMP. We are going to have electrolyte levels. And this is one of the most important things for me as an ER nurse. You come in off the street. I want to know right now-- if I am looking at you in my ER, I want to know your electrolyte levels, right? So I want to know what is your sodium, your potassium. What is your calcium and your chloride. An important thing to note is that magnesium is not included in the basic metabolic panel. That is a separate lab that must be ordered. So do not think that this is telling you comprehensively everything there is to know about the electrolytes. It is going to give me those big four, essentially. So that is really important critical information.

It is also going to tell me about the glucose level. Remember, this is a metabolic panel. So what does my body need to do metabolism? Glucose, right? And then it is also going to talk to me about the byproducts of metabolism. What is going on with my kidneys. How well are my kidneys functioning. So it is going to give you some information there. You may see creatinine and BUN, blood, urea, nitrogen. Depending on your facility, you may also have something called an EGFR, an estimated glomerular filtration rate. There may be some more information for you when it comes to what exact kidney function tests are in yours, but with certainty, creat and BUN will be in there. As those rise, that tells me we are not getting rid of the byproducts of metabolism very well at all, and that gives me concerns. It could also tell me that my patient needs more fluid. So this gives us some information. And then along with the kidney function, it is going to tell us about carbon dioxide. And you might be thinking, "Carbon dioxide, why is that in this?" It is a metabolic panel. What is a byproduct of cellular respiration? Carbon dioxide. So yes, this is a venous level of carbon dioxide, so keep that in mind. This is not an arterial blood gas, okay? So CBC, we are looking at formed elements and cells. BMP, we are looking at electrolytes. We are looking at chemicals. We are looking at what are the chemicals making up the blood.

And lastly, in this video, I am going to talk to you about liver function panel. Now, I want to preface this by saying, you may hear me throughout the course of these videos refer to these as LFTs. That is what my hospital facility calls it and what I have always called it in previous facilities. That stands for liver function tests. But I just want you to understand that if you hear LFTs or liver function panel, it is the same thing. Now, what goes into a liver function test, a liver function panel, is going to be information about the liver. And that seems silly but think about the things that happen in the liver and you can get there. So I need to know things about protein. How much total protein. How much albumin. I need to know about the byproducts, things like bilirubin, right? I need to know about the liver enzymes as well. And liver enzymes, I am going to talk to you very, very briefly, and we are not going to get in the weeds about it, but alkaline phosphatase, ALP, alanine aminotransferase, ALT, and aspartate aminotransferase, AST, these are the three liver enzymes that are going to be part of your basic-- I am sorry, of your liver function tests, where we are looking to see what is going on with the liver. I have talked to the kidneys already. I know what is going on with them. I checked them out in my BMP. I have looked at the cells in the blood, right? I know what is going on there. But I want to know, what is the liver up to? How much protein is in this liver? How much albumin is helping to bring fluid in or out of that vascular space? What is going on with their liver function? Do they have an injury, an acute or a chronic liver injury, right? We are going to look at all of these things and get more information through doing these tests.

All right. You stayed to the end, and I am so glad because I have a couple of questions to test your knowledge of key facts provided in this video.

The nurse notes new onset of jaundice in a patient who has been on the unit for several days. Which lab panel should the nurse anticipate for further investigation?

A liver function panel.

Which lab panel should the nurse anticipate for a patient who may be experiencing internal bleeding?

A complete blood count.

The nurse is concerned about the potassium level in a patient who missed his hemodialysis appointment. In which panel would information about his potassium be found?

The basic metabolic panel.

A patient reports to the ER nurse that he was sent over from urgent care due to concerns for pneumonia. Which panel may help provide information about the severity of his infection?

A complete blood count with differential.

All right. That is it for this video. Thank you so much for watching. I hope you learned something. And if you did, it would mean the world to me and to other learners if you would tell us what you learned, or if you have a great way of remembering something that I did not mention. Thanks so much for studying with me, and I will see you in the next one.