So yeah, I am I'm super excited to talk about this. And as, as Nora alluded to, the cases that we're going to talk about today are a little bit on the complex side, except for my cat, mainly because that's the that's the land I live in. So, please be advised, like, not every, you know, Addisonian is going to come in looking as bad as the one that we'll talk about. You know, disease exists on a spectrum, and that's that's okay. It's just that I'm living at one particular extreme end of that spectrum. 

All right. So, the way that we're going to go through this is we're going to talk a bit about the factors that affect testing. That's kind of our warm up. And then we'll talk about liver values, pancreatic enzymes and cholesterol, kidney values, protein and muscle enzymes and electrolytes. And please understand that like while I have broken this into apparently discrete categories, we know that there's actually a lot of overlap between these things. So there are some kidney diseases that can affect your cholesterol. There are liver diseases that can affect your cholesterol. Thyroid disease can affect your cholesterol. We're not going to get through every single disease. We're going to do kind of a broad strokes overview. And this is if you haven't seen a chemistry yet this is about what it looks like. So you have the analyte that you're looking at, the patient's value, the reference interval. And then oftentimes there's this nice little visual chart so that you can kind of look and be flagged like all right this patient's, oh, creatinine is low, I don't have to worry about that. So versus over here the ALT is on the high side. So that's kind of how a chem is usually set up. And I'm going to use the word chem, chem profile, chemistry and profile all interchangeably to talk about that big panel of tests. 

So one of the things that we have to be really mindful of is sample handling and collection and how we take care of our machines. So usually the machine maintenance schedule and how the machines are maintained and kind of tuned up, flushed reagents, all that sort of stuff is established by the company that makes the analyzers themselves. And they'll come out and service them at your clinic, if that's, if that's the arrangement that you've made. And then you also need to establish reference intervals. And each lab establishes their own. And this is because each machine has some instrument and reagent dependent aspects of it. When you're establishing reference intervals, what you're doing is you're taking blood from a large population of healthy adults, not on medications that affect lab results. You know, female patients that are not late in gestation or early lactation and ideally from a uniform environment, and you're taking samples from those animals, and then you're putting them through your analyzer and you're trying to figure out like, what is the average range of glucose or the average range of BUN that this population has when the blood is run on this analyzer and then there's a whole lot of stats. I don't do a lot of stats. But there are people out there that do and that love them and thank goodness for that. And then they establish reference intervals. You also have to make sure that you have the appropriate sample type. So if you take a, a blood tube that, that has, an anticoagulant that binds all the calcium, and then you try to assess what the blood calcium is, you're not going to get accurate results on that. So keep that in mind as well. 

The way these analyzers work is that they use a combination of color and light passing through the sample to give you the actual, value that gets printed out on that piece of paper. So be mindful that excess color or haziness makes interpretation difficult. And the main things that we see that become problematic are hemolysis. Hemolysis is when red cells get lysed up, and then the interior contents, a.k.a. hemoglobin, gets released into circulation and it makes the serum a little bit more, kind of reddish in color. This can happen if a patient has a disease where they're destroying their own red cells, or they have gotten into certain toxins like onions, garlic for small animals. Or collection, so we can cause hemolysis as well. So if we, don't do our venapuncture, diligently or maybe the vein is very small and collapsed, and it's very hard to get blood from the patient, or if you're, retracting that syringe and that plunger a lot, or if you're moving blood from the syringe to the tube and you're pushing all the blood out of the syringe and into that tube, and then you shake it around, you're going to break up some of those red cells and give rise to some of the hemolysis that we we could see. The next thing that can cause more haziness is lipemia . So this is due to circulating triglycerides. So over here we have a really nice example of lipemic serum. So this tube is an EDTA tube has an anticoagulant in it and it was just let it sit for a period of time and then the red cells fell to the bottom, the serum rose to the top. And you can see it's kind of creamy, almost looks like butter. And so lipemia can occur after a meal or secondary to specific disease states as well. And then icterus is due to increased bilirubin in the bloodstream. And bilirubin is a, product of the breakdown of hemoglobin. So sometimes you have a patient that has immune destruction of their red cells. They have a lot of spillage of hemoglobin into circulation. They might have hemolysis. But then as the liver's trying to clean all of that up, then they can develop some degree of icterus also called jaundice, so yellowing of the eyes and the serum and the gums and and the urine, like everything in the patient, turns a little bit more yellow. 

The tubes that you use matter as well. And this is not a completely exhaustive list, but this is the list of the tubes that you're going to see most likely in practice. Lithium heparin is a type of anticoagulant, and it's in a green top tube. If you centrifuge it, it yields plasma. And for certain, chemistry analyzers, you can actually use that plasma to, to run a chemistry, which is kind of nice. A plain tube doesn't have anticoagulant. If you put blood into it, it will clot over time. If you centrifuge it out, it yield serum. You can also use plain top tubes for, like, this white one down here in the corner, you can use these also for urine or other fluid samples, joint fluid, chest fluid, belly fluid, I mean, kind of all sorts of things. A silicon gel tube is one with, red, and it's usually kind of speckled or gray top tube. And what these tubes have is they have this gel in them that helps the serum separate from the red cells. And then after you centrifuge it, the red cells are on the bottom. There's this layer of kind of, gel stuck substance. And then the serum's on top. And what's nice about this is that you can take this tube and you can, you know, just like you can turn it upside down or whatever. And the cells and the serum are going to stay separated. If you have a plain top tube, yes, the blood will be clotted but if you start kind of turning that tube over or rolling it around, there's going to be some admixture between the serum and the, the rest of the clotted blood that's in there. An EDTA anticoagulant tube is purple top, and that you usually just don't centrifuge that. And then a citrate anticoagulant is a blue top tube. And if you centrifuge it, that's going to yield plasma. And just make sure that you store them appropriately based on the sample that you're doing or the test that you want to run.