Lab Values for GI (Nursing)

by Rhonda Lawes, PhD, RN

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    00:01 Let's talk about lab values, we'll talk about that as an option.

    00:03 And I will talk about key lab values for the GI system.

    00:08 These three.

    00:08 Serum albumin and prealbumin, you'll see most often but I also want to introduce you to transferrin if you have not been introduced to that yet.

    00:18 Let's start with the first one, serum albumin.

    00:22 Now have you stopped to think What does albumin represent in your body? I just happen to have the answer for you.

    00:29 Now what serum albumin represents in your body is protein, because see, a healthy liver, even one that is a geriatric liver, transforms the protein that you ingest into albumin, so it takes what you eat.

    00:44 Remember, you've got those massive vessels that come up from your intestines, back up to your liver, there it can transform the protein that you eat, and turn it into albumin.

    00:55 We measure that on a lab test called serum albumin.

    00:59 Remember, lab work is drawn right from a vein, a serum albumin would be drawn from a vein.

    01:03 And that's what we're measuring when we say serum albumin.

    01:07 So the protein doesn't matter if the source is animal.

    01:11 So if you're sitting down to a big steak, or if it's a plant source of protein - same thing.

    01:17 A healthy liver is going to turn the protein that you eat into albumin in your blood.

    01:23 And it does some amazing things like serum albumin is charged in a way that it will attract sodium, and albumin - it's this really big thing that's not meant to go through the capillary.

    01:38 So it should stay in your intravascular space and draw the appropriate amount of fluids into your intravascular space.

    01:46 That way you can maintain an adequate blood pressure.

    01:49 So serum albumin does let us know about nutritional intake and how the liver's doing but it also is going to impact their fluid volume bowel, so it's really important.

    02:01 So you see there, we did that you took the protein in and you watch the liver, turn it into albumin just to reinforce that concept in your mind.

    02:11 Now, if the liver isn't functioning correctly, you'll notice on our graphics, just the look of the liver changes, right, we did that to kind of help you recognize this is when the liver isn't fully functioning or not functioning as well as it could.

    02:25 If the liver isn't functioning well, it would make sense that it can't turn that protein into albumin as efficiently as a healthy liver can.

    02:35 So you're likely going to see a decrease in serum albumin.

    02:39 So if I'm working with a client, and I look at their serum albumin level, and it is low, I always want to think, 'Ah, wonder if they're showing me any other signs that they could have a problem with their liver.

    02:51 So that's why a health care provider could order this test.

    02:55 They either are trying to assess the livers ability to take dietary protein and turn it into albumin and also be a lab work that they draw if the client has that unexpected weight loss.

    03:05 Remember, we're always looking at the trend of a patient's weight, not judging them if they're under or over.

    03:12 We're looking at the trend of their weight and if they've had a change in their weight, they've lost weight, and they have a lower serum albumin, we know we need to investigate even further.

    03:24 We've put the normal value, the ranges for serum albumin on the screen.

    03:29 I don't want you to get so focused on the numbers.

    03:31 They're just there as a reference and keep in mind depends on where you're practicing , what country you're practicing in, which lab is doing the lab work as to what will be the normal range.

    03:43 But whenever you get your lab work back, that laboratory will report what they see as a normal range.

    03:50 Keep in mind, these are going to vary from lab to hospital to different place.

    03:54 So, you may even have some different units.

    03:57 We've just put up some examples of what you might expect for a normal serum albumin range.

    04:04 Now, prealbumin was the second one and I want to talk to you about what prealbumin represents in your body.

    04:14 Now, pre albumin is a protein, well, that's going to be easy to remember because we knew albumin is a protein, so prealbumin is also a protein.

    04:23 And it's also made in your liver.

    04:26 Okay, cool.

    04:27 So both prealbumin and albumin are made in your liver.

    04:32 Now, what prealbumin does that's a little different is it helps carry thyroid hormones, and vitamin A through your bloodstream.

    04:40 Whoa, okay, that's different than serum albumin, right? Because we talked about the way a serum albumin is, it's charged in a way that attracts sodium and then you've got water that comes into your intravascular space.

    04:53 But prealbumins job is a little different, and that's why we have it, because its job is to carry thyroid hormones, and vitamin A through your bloodstream.

    05:04 So what can we learn from a patient? Well, before we talk about that, look, as you see the animation we here have for you here.

    05:12 So you can kind of understand how prealbumin works.

    05:17 So the obvious question is, why would a healthcare provider order a pre albumin test? Well, a pre albumin test is going to give us a little more information about the patient's recent nutritional status.

    05:30 Albumin encompasses a longer period of time, but prealbumin tells me what's gone on most recently with this patient.

    05:38 So they're going to look if they need that particular information.

    05:42 That's why they would order a prealbumin test.

    05:45 Now, some signs that you may have seen, some cues is when you weighed the patient, and then you recognize the patient had experienced unexpected weight loss.

    05:54 Health care providers likely to order a prealbumin.

    05:57 Now, if the scores come back outside of the normal range, let's talk about high prealbumin scores.

    06:04 This tells us we have another problem.

    06:07 Now, it could be a sign of long term chronic kidney disease.

    06:10 The patient may or may not know that they have it.

    06:14 But we know we're going to work through these diagnoses and see if the patient has any other indicators of kidney disease, steroid use or maybe something like alcoholism.

    06:26 Now there are several other causes of a high prealbumin score.

    06:30 We just narrowed it down to these three to kind of give you three most important that will stick in your mind.

    06:40 We've got a normal range there for you on the screen.

    06:42 Remember what we always say, ranges can vary by laboratory and you may use a different type of unit where you're practicing.

    06:50 So be sure to check your protocols.

    06:54 So let's go back to what is the difference between prealbumin and albumin serum tests.

    07:00 I'm going to pause for a minute because I know you can answer this.

    07:10 Okay, let's break it down and see how much you're able to remember and get correct.

    07:15 Prealbumin is a precursor to albumin, so that means it comes before albumin.

    07:21 Now, it's a really good marker of your protein status, specifically, your visceral protein status.

    07:27 Now, this is affected earlier by acute changes in your protein balance.

    07:32 This is going to let us know what's gone on in the previous week. Right? Because its half-life is like 2 to 4 days.

    07:38 So are prealbumin and albumin related? Yes.

    07:43 Do they have different jobs? Yes.

    07:45 Albumin is a precursor, right? Prealbumin is a precursor to albumin.

    07:52 That's why those three letters - PRE, make it very easy to remember.

    07:57 Now we can use an albumin test and they say, it's often used as a surrogate marker of nutrition.

    08:01 So it's not the worst test for knowing what their nutritional status is.

    08:06 But it's not as good as telling about what's happened recently.

    08:10 Because look at the half life of albumin, it's 21 days.

    08:15 Well, the half life of prealbumin is 2 to 4 days.

    08:18 Because prealbumin doesn't stick around as long as albumin, then we know that we'll know much more information about what's happened recently as far as nutrition versus the longer period of time with the half life of 21 days.

    08:31 So it's not as valuable if I'm wanting to find out what has happened most recently.

    08:37 Now why have we repeated that multiple times? Because it's really an important concept.

    08:43 Albumin is a very prominent protein in your body, you need to understand and be able to recognize the differences and the similarities between prealbumin and albumin and what information we get from the lab test.

    About the Lecture

    The lecture Lab Values for GI (Nursing) by Rhonda Lawes, PhD, RN is from the course Assessment of the Geriatric Patient: Gastrointestinal System (Nursing).

    Included Quiz Questions

    1. Albumin
    2. Transferrin
    3. Hemoglobin
    4. Lipase
    1. Prealbumin
    2. Transferrin
    3. Albumin
    4. Lipase
    1. It has a longer half-life than prealbumin.
    2. It is a better marker of visceral protein status than prealbumin.
    3. It shows variations in protein balance sooner than prealbumin.
    4. It is the precursor to prealbumin.
    1. To investigate unexpected weight loss.
    2. To assess the client’s nutritional status over several months.
    3. To assess the extent of blood loss a client has experienced.
    4. To investigate an unexplained rash.

    Author of lecture Lab Values for GI (Nursing)

     Rhonda Lawes, PhD, RN

    Rhonda Lawes, PhD, RN

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