00:00
Hi, welcome to our video series
on interpreting lab values.
00:05
In this portion of the series,
we're going to look at a
urinalysis microscopic exam,
but we're looking specifically
at urine casts.
00:13
Now keep in mind, cast in the urine
indicate kidney disease
versus a lower
urinary tract disease.
00:20
So we pay really close
attention to these.
00:23
Before I go on,
I want to make sure
you are crystal clear on that.
00:30
Cast in the urine indicate
we've got a kidney problem.
00:34
It's not a lower
urinary tract problem,
it's definitely a kidney problem.
00:38
Here's why.
00:39
Casts are formed in the lumen
of the nephron of the kidneys,
and then they are excreted
in the urine.
00:46
That's why we know
we got a kidney problem
because casts are formed in the
specific anatomy of the kidney.
00:53
Now they're made up of these
hardened proteins and other cells.
00:58
So identifying the other cells can
give us really important information
about the conditions in the nephron.
01:05
Okay, I don't want to go on
until we're really clear
on what this content is.
01:10
Casts, tell me
I've got a kidney problem
like right in the kidney?
Why?
Because cast are formed
in the lumen.
01:18
And we say lumen,
that's the opening of the tube
in the nephron, right?
So that's why they're shaped
kind of like a tube.
01:26
What are they made up of?
A hardman protein
plus other cells.
01:31
So cast usually have a
hardman protein, and other cells.
01:36
So it's those other cells,
if we can identify them,
they can give us really
important information about
specific conditions in the nephron.
01:46
So who's most likely
to develop a cast?
So what type of patients or what
things are going on in their body
that make them most likely
to develop cast?
Low renal flow is one of them.
01:59
Now let's think about that.
02:00
Cast, are hard protein.
02:03
Think of them as kind of a mold,
and then these
other cells get in there.
02:07
So how would low flow
make that a problem?
Well, if I'm going to make a mold,
I would like things to be moving
through very slowly, right?
If things are whipping
through that kidney,
you're not likely to have
many casts developed.
02:21
What about high salt concentration?
Yeah, this helps make an environment
that's really friendly,
the cast being developed.
02:29
The third piece is low or acidic pH.
02:34
So if a patient has casts,
they likely have low renal flow,
meaning they've got some
kidney damage,
probably a high salt concentration,
and a low or acidic pH.