Low Urine Specific Gravity: Patient Care (Nursing)

00:01 Hi, welcome to our video series on interpreting lab values.

00:05 We're going to take a look causes of low urine specific gravity.

00:09 Now, when we're talking about urine specific gravity, we're looking at a ratio of the density of urine compared to pure water.

00:17 Pure water has a density of 1.00.

00:21 Normal urine specific gravity is 1.010 to 1.030.

00:26 Now, have you ever stopped and thought about why is the specific gravity of urine higher than water? Well, water doesn't have anything dissolved in it.

00:35 Urine has the other things the other substances dissolved in it minerals and other types of compounds.

00:42 That's why the urine specific gravity is higher than pure water.

00:46 Now, if you're looking at this range here, you see we've got three boxes for you.

00:51 So I want you to look at the first box there's the normal value, we just talked about it.

00:56 We're looking at causes of low urine specific gravity.

01:01 So we know that the more dehydrated a patient is, the higher the specific gravity number will be because there's less water in there and it's more concentrated.

01:10 So the first box is normal.

01:13 The third box is looking at highly concentrated urine.

01:18 Now let's try your attention to the middle box.

01:20 You notice that that is showing numbers closer to 1.010 or lower.

01:28 So we're talking about less than that.

01:30 That's what a low specific gravity is.

01:33 So that means we have more water and less stuff dissolved in it.

01:39 So looking at our magical five bladders, if you look at our other videos, you've seen this before.

01:45 If a patient's urine specific gravity is 1.003, What do you think their urine would look like? Would it look like that red one at the end, yeah? No.

01:58 We know that water is 1.00.

02:03 So if I've got 1.003, that is just a smidge above water, right? So I'm definitely going to be all the way down at the other end.

02:14 Where it's going to be transparent to very pale yellow.

02:18 That tells me there's a lot of water there and not much dissolved in it.

02:23 So let's take a look at this and apply it to patient care.

02:26 Again, my favorite part. Because there's learning and then there's learning how to take care of patients, and that's what we're talking about.

02:33 So with the urine specific gravity result that's 1.003.

02:39 Let's look at what that means to your patient.

02:41 What does that indicate about their fluid volume status? What do you think? Are they overloaded or are they dehydrated? Well, if they're dehydrated, we know the number goes up.

02:55 Since that number is 1.003, that is low than normal.

03:01 So they're not dehydrated, and they're outside of the normal range.

03:06 So they must have extra fluid on board.

03:09 That's right.

03:09 That's why, their urine will likely look almost transparent to a very pale straw color.

03:17 Now, let's look at a patient's urine specific gravity.

03:20 And it's been unchanged over the past three days, and it remains at 1.010.

03:27 Yeah, I don't know how to tell you this is really bad.

03:30 Your kidney has become the equivalent of a pet rock.

03:33 It doesn't do anything.

03:34 And that means whatever flows into it, flows through it, and flows out of it unchanged.

03:41 So if a patient has urine fixed specific gravity, that means it stayed at 1.010 for three days, that is not a good sign.

03:52 I mean, the kidney isn't doing anything to change the concentration or dilution of the fluid as it moves through the kidney and exits the body into urine.

04:01 So ominous sign.

04:04 That kidney is not doing anything it was designed to do.