00:01
Okay, so we talked
about assessing GFR
and measuring kidney
function that way
but there's another way
that we can also
measure kidney function
or assess how kidney
function is doing
and that is really by
looking at proteinuria
that's protein in the urine.
00:15
So it's really defined
by abnormal quantities
of protein in the urine
and we talked about remember before
at the beginning of the lecture
that this is really a clinical
marker of kidney damage.
00:25
Just to remind ourselves,
normal quantity of
protein in the urine
is typically less than than a
150 milligrams over a
24-hour period of time.
00:35
And we also talked
about how albumin is
the principal component
of protein in the urine.
00:40
And typical amounts of albumin
are about less than
30 milligrams over
a 24-hour period of time.
00:49
So when people exceed that
then they have an abnormal
amount of protein in their urine.
00:54
So there are a couple
of different methods
that we can use in order to
measure protein in the urine.
01:00
Number 1 and probably what's
most simple for people
is to just do a urine dipstick.
01:04
This is essentially
in a colorimetric test
that doesn't really quantify
the exact amount of protein
but it tell it, does tell you
whether protein is present
depending on how dark that
urinary dipstick colors.
01:17
Now another more accurate
way to look at things
as actually getting a 24
hour urine measurement
for protein collection.
01:23
So this is going to
provide us a total protein
the total amount of protein
that's excreted in the urine
over a 24-hour period of time.
01:30
If we do this we do need to
measure urinary creatinine
as well to ensure
that that our patients have
obtained inaccurate collection.
01:38
But we just talked about
before we were at talking
about creatinine clearance
how difficult it really is to
do a 24-hour urine collection
and you really don't want to
have your patients do that
over time in order to
follow their proteinuria.
01:52
Now we can use something else called
the protein to creatinine ratio,
or the albumin to
creatinnine ratio.
01:58
This is actually a spot
urinary measurement of protein
or for albumin and we
measure that to creatinine.
02:07
It's going to estimate a 24 hour
urine protein or albumin values.
02:10
So what somebody excretes
within a 24-hour period of time
So most people will generate
between about one to two
grams of urinary creatinine.
02:20
And this is how we can use this.
02:22
So I'm going to illustrate
a couple of points here.
02:24
In men,
They usually generate somewhere
between 20 to 25 milligrams
per kilogram of urinary
cretinine daily again,
assuming that they
have more muscle mass.
02:33
So if I have an 80
kilogram gentleman,
then he's going to make
about 1600 milligrams
of urinary creatinine.
02:41
That's the amount of protein
that he's going to excrete
in his or that's the amount
Of creatinine that's he's
going to excrete in his urine.
02:48
If I have a woman
again presuming that she has
less muscle mass than a man.
02:53
Usually women will generate
somewhere about 15 to 20
milligrams per kilogram
of urinary creatinine daily.
02:58
So if I have a 60
kilogram woman,
then she's going to generate
somewhere around 900 milligrams
of urinary creatinine.
03:05
So you can see that
between 900 and 1600
most people again are close
to that spectrum of one
gram of creatinine daily.
03:14
So the way I can estimate
how much protein somebody
has in their urine
As I basically take an aliquot
of urine at a random time
and that is going to give
me that urinary protein
or urinary albumin measurement.
03:26
I take an aliquot in that
same aliquot of urine.
03:30
I'm going to get
that spot assessment
of urinary creatinine.
03:33
If I take that ratio,
then that gives me
the amount of protein
estimated that they make within
a 24-hour period of time.
03:41
Now you can see
because men generate
a little bit more
creatinine than women,
then it's probably
going to underestimate
with their true proteinuria is,
and in women,
it might slightly overestimate
the amount of protein that they
make in a 24-hour period of time,
but what's really helpful about
the using these spot ratios.
04:01
Is it something that we
can follow over time?
And it's something that
we can use to assess
therapeutic targets
and make sure that the
medications and other things
that we're doing to
treat our patients
are actually working in
decreasing proteinuria.