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In this lesson we’re going to take a look at total bilirubin
Bilirubin is a marker that we use to take a look at liver function. The normal value is in 0.1 to 1.2 mg per deciliter, and it’s often measured with direct bilirubin. In order to understand why we measure it, we need to look at how it works.
So we have all these millions of red blood cells in your body, and eventually they don’t work anymore, and they need to be broken down. Part of that breakdown means that heme, the iron-containing compound in red blood cells, needs to be broken down, and what facilitates this is bilirubin.
Bilirubin comes in two forms. It comes in conjugated, and unconjugated. Conjugated bilirubin means that it’s water-soluble, and that means that it can be transported out of the body most of the time by the digestive system. The unconjugated form is not water-soluble. So what happens is the unconjugated bilirubin is sent to the liver, and is then converted to conjugated bilirubin, and then that excreted out through the digestive system.
Now a problem that we run into is that when the liver stops functioning appropriately, you get this buildup of bilirubin because it can’t be broken down by the liver. So what ends up happening is your patient can experience things like jaundice, or icterus, which is a yellowing of the white portion of the eye. Essentially, bilirubin is an indicator of liver dysfunction, and we should take a closer look at our patients that have high bilirubin to see what’s going on with your liver.
Bilirubin is often included with liver function tests, and sometime some larger chemistries , and you’re going to send these off to the lab in a green top tube.
You’re going to see elevations of total bilirubin in patients that have some sort of liver disease, so they could have alcoholic cirrhosis, or different type of hepatitis, whether an infection or viral. You’re also going to see it in cases where the gallbladder is affected, so cholecystitis or biliary obstruction. You’re also going to see it in cases of liver tumors, or in cases where red blood cells are being broken down too fast, so you might see this in certain autoimmune diseases. You’re going to see it most prevalently in newborn jaundice.
Unfortunately newborns don’t have the ability to properly break down that bilirubin like they should. So we do things like this, which is called phototherapy. Bilirubin is extremely susceptible the light, and break down easily under photons, or light therapy. So we very commonly will use for the therapy for extremely jaundiced patients. Decreased levels of bilirubin are ideal, so you will rarely see a total bilirubin of less than 0.1.
For our nursing concept with total bilirubin, we’re looking at the lab values of our gastrointestinal and liver metabolism, so that’s why.
So let’s recap.
Normal values for total bilirubin are 0.1 to 1.2 mg per deciliter.
Bilirubin is required for the process of breaking down heme, and then it sent to the liver to be excreted.
If you have a buildup of bilirubin, it indicates that there’s a problem with the system. So you’ll probably need to take a look at the liver and see what’s going on with it.
Bilirubin is very sensitive to light, so that’s why we use phototherapy for treating newborn jaundice.
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