Lab Values, part 2: Lab Panels - CMP, Lipids, Thyroid Panel, ABG

Hi, I'm Meris. And in this video, I'm going to be talking to you about four common laboratory panels, the complete metabolic panel, CMP, the lipid panel, thyroid panel, and arterial blood gas, ABG. I'm 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 and at your fingertips wherever you are. All right, let's go ahead and get started.

So first up, we are talking about the complete metabolic panel. And if you refer back to the previous video, you can see where I talked to you about the basic metabolic panel. Good news, if you've mastered BMP and the liver function tests that we talked about in the previous video, then you've basically got the CMP put together already. The comprehensive metabolic panel, CMP, is just the basic metabolic panel plus some additional tests that tell us about the status of our patient's liver function. So when I think about CMP, I think of this as giving me much more of a global view of the metabolic processes going on in my patient. This is letting me look both at the electrolytes and the kidneys and all of the things that we talked about in BMP; however, it's additionally adding in that information about the liver function. Very helpful test, especially for somebody like me who is an ER nurse. It is something that we see with frequency.

The next test I want to talk to you about is the lipid panel, and there's a few things in here that you should be familiar with. So there's the total cholesterol level, the triglycerides, the high-density lipoprotein, which is HDL, and the low-density lipoprotein, LDL. Depending on your facility, you may have a couple of other values in there such as VLDL, very-low-density lipoprotein. You may see some other stuff, but the point here is that we are examining in depth the different types of lipids that may be found in our blood. This is going to give us great information. This is a really good screening tool at your annual physical. They will be looking to see if you have any signs of hyperlipidemia, elevated cholesterol. This can also give us information about what's going on right here in this moment. Do we have somebody who has some kind of a situation where I think, "Man, their blood looks really fatty"? We can add a lipid profile on and see what the exact lipid composition of that blood is. So very important there in monitoring for patients who are taking statins, for instance, or any other cholesterol-lowering drug. That's going to be an important lab panel that you should be keeping your eye on.

So up next, we're looking at the thyroid panel. And as the name would suggest, this is going to be giving us some information about the different hormones that play a role in my thyroid function. So of course, right off the jump, you know one of the most important ones is going to be the TSH, the thyroid-stimulating hormone. That's going to tell me what's going on at the level of the brain to stimulate the thyroid. And then I'm going to look at two other values. I'm going to look at the free or total T4 and T3. Now, T4, you might know better as thyroxine. And T3, you might know better as - and bear with me, because we're going to get through this pronunciation together - triiodothyronine. There we go. Triiodothyronine. Try for three, right? That's how you can remember that that is T3. So again, your mileage may vary. Your facility might have some additional values in this panel. But the point here is that we're looking at the function of the thyroid and nothing else when we're looking at a thyroid panel.

And lastly, I'm going to talk to you about the arterial blood gas components, or ABG. And before we start, I do just want to let you know if you need help interpreting ABGs, we have so many resources to help you. We, of course, have information here in the cards for you. But additionally, we do have an entire video series on ABG interpretation plus an ABG interpretation course, which is available through our Level Up RN membership. So that's not what this is. This, I'm just going to talk to you about some of the components of the ABG.

So in the ABG, you know one of the most important things that we're going to look at is, what is the pH of that arterial blood? Is it acidic, is it alkaline, or is it in that perfect homeostatic range that we love so much? We're also going to look at the partial pressure of oxygen, PaO2; the partial pressure of carbon dioxide, PaCO2; the saturation of hemoglobin with oxygen, SaO2; we're going to look at bicarbonate HCO3; and we're also going to look at something called the base deficit or excess. So you'll hear that called the base deficit or BE for base excess sometimes. Just depends on your facility, what they call it. But these are the different components that are going to go into our arterial blood gas.

So who is getting an arterial blood gas? That's a great question. It's certainly not everybody. This is mostly going to be anybody that we have a respiratory concern for. If I think something is going on with their respiratory status and I need to know, how well are they compensating? How well are they doing? Then yes, this might be somebody that I'm getting an ABG on in the ER.

Now, my ventilated patients, meaning that they are on a mechanical ventilator, they are receiving positive pressure ventilation, well, what this means is that this person is not in control of their own respirations most of the time. And so if they're not in control, then they cannot make any sort of compensation. They cannot adjust how often they breathe, or how much volume is delivered to their lungs, or what the fraction of inspired oxygen is, or what the pressure used to deliver it is. Any of these things, they cannot regulate any of this, which you and I do, breath for breath, right? I regulate the rate at which I'm breathing. I regulate the volume with which I breathe based on what's going on in that situation. So you've taken away that ability in somebody who is receiving mechanical ventilation, especially if they are sedated and/or paralyzed.

So when we talk about that, yeah, this should be a person that gives you a red flag that says this patient needs more frequent ABGs than just a general respiratory patient. The body cannot do anything to change the respiratory status, so I need to keep a close watch on those values and see what's going on with their respirations to make sure that I don't need to make any adjustments. This is predominantly going to be done in the ICU, however, absolutely takes place in the ER. And depending on your facility and what kinds of patients you have and what your policies are, this could also be present in a progressive or a step-down or intermediate floor as well, depending on what you call it. So that is the component of an ABG and the purpose behind ordering it.

One thing I do want to mention is that we don't go into depth into a VBG, a venous blood gas. However, it's going to have many of the same components. What you need to know is that it's going to have slightly different values because we're testing venous blood and not arterial blood. So it is important to use the reference ranges provided by your laboratory, and don't use those hardwired ABG numbers that you're going to have stamped in your memory for the rest of your life, right? It's important to remember if you're using a VBG that we are looking at venous and not arterial blood.

All right. That is it for this video, but I am so glad you stayed until the end because I am going to test your knowledge of key facts provided in this video with some quiz questions.

The nurse is caring for a patient who takes atorvastatin and is present for his annual physical. What panel should the nurse anticipate being ordered to assess the efficacy of this treatment regimen?

A lipid panel.

The nurse is caring for a patient who is receiving mechanical ventilation at APRV settings. Which lab panel is most appropriate to monitor their respiratory status?

An arterial blood gas.

A patient taking levothyroxine for hypothyroidism complains of tachycardia, weight loss, insomnia, and heat intolerance. Which lab panel would be most appropriate to examine the efficacy of their treatment regimen?

A thyroid panel.

All right, that is it for this video. I hope you enjoyed it and that you learned something. If you did, would you leave us a comment and let me know something that you learned? We love that feedback. And also, if you have a great way of remembering something that I didn't mention in this video, I'd love it if you'd leave a comment so that we can see it, but also so that other learners can see it as well. All right, that's it for this one. Thanks so much, and happy studying.