okay here we are part two of clinical
chemistry let's go we're gonna start by
talking about kidneys so you all know
that kidneys play a major role in
maintaining homeostasis their primary
function is to control water and
electrolyte levels in times of abnormal
balance so with maybe an animal's not
taking in enough water or maybe too much
that sort of thing so they excrete or
conserve hydrogen ions to maintain blood
pH again we talked about why that's
important blood pH has to be maintained
in a very very narrow range in order to
make sure that all of our enzyme induced
or catalyzed reactions happen as they
are supposed to kidneys will conserve
nutrients when they need to they remove
end products of nitrogen metabolism
which of course if they get built up in
the body will really severely alter the
pH and other things
and they produce running erythropoietin
prostaglandins and they help with
vitamin D activation very very important
of course there are a few primary
chemistry tests for kidney function
these include urea nitrogen which we
usually just call urea or blood urea
nitrogen or B UN creatinine we'll talk
more about that as well so other tests
include different assays to evaluate the
rate and the efficiency of glomerular
filtration and I'll go into a bit more
detail on that shortly
let's talk vun so urea is the principal
end product of acid breakdown in mammals
bu n is used to evaluate kidney function
on the basis of the ability of the
kidney to remove nitrogenous waste which
is urea from the blood so we're checking
to see how effectively the kidneys are
getting rid of B UN under normal
conditions all the urea passes through
the glomerulus and will enter the renal
tubules and then how about half of it is
reabsorbed the rest is excreted through
the urine if the kidney is not working
right then not enough of the urea is
actually eliminated from the body and
that increases bu n levels and we can
easily measure those contamination with
urea is producing bacteria can interfere
with bu and results they deke for that
would decrease viewing levels and it can
be easily prevented though by analyzing
the sample within an hour of collecting
it so that's why timing is always
important we don't want to collect our
samples and then wait a few hours and
then test them so run them as quickly as
you can and that shouldn't be a problem
there's a couple of different kinds of
tests ones a photometric tests it has an
acceptable level of accuracy and then
there's the chromatographic or dipstick
tests that we can use that we often do
use for blood if we're just looking for
P um and that is a screening test this
is an example of a dipstick
some of you may have used these in
practice they used to be used all the
time it was a really quick way to have a
look at just the urea and how so
basically how well the body is getting
rid of vun of the urea nitrogen so
really easy to use just like a urine
chemistry stick and so if those are
those of you who've been to practice may
have seen these and sticks we don't use
them so much anymore because again they
are a screening tool and usually we want
a bit more information than they'll give
us so it must be extreme excreted in a
high volume of water so that means
dehydration can cause an increase in V
um we get retention of urea in those
cases which leads to ischemia
high-protein diets have high levels of
amino acids and that's going to result
in high v1 and then strenuous activity
breaks down amino acids and can result
in an increase in v1 as well age and
sacral can cause differences in urea
values so just be aware of that I have
not found it to be a terribly
significant determinant of
hi buin let's talk about creatinine
cramming is formed from creatine which
is found in the skeletal muscle it's a
function of the muscle mass of an animal
so large and those with a large muscle
mass will tend to have larger creatine
and thus creating levels but it diffuses
out of the muscle into the blood and the
creatinine level tends to be constant in
any animal regardless of what its muscle
mass is those basically normal
creatinine for that animal which again
may be higher if the animal has higher
muscle mass any condition that alters
the glomerular filtration rate will
alter the crown mean the levels we use
serum creatinine to evaluate for normal
renal function unfortunately it's not an
early indicator of kidney disease
basically about three-quarters of kidney
tissue has to be non-functional before
the levels of cratan will rise luckily
there are new tests coming out one in
specific that actually are starting to
detect kidney disease earlier I'm not
covering that in this lecture but
perhaps I'll talk about it down the line
but for now urea and creatinine tend to
be the ones that we use in clinic boasts
more than any others so let's just say
they're not great tests but they do help
us diagnose kidney disease there are a
couple of ways to do these crowning
tests as a Jaffee method enzyme and
somatic methods don't worry about it
basically these numbers will come out of
your automatic automatic chemistry
analyzer we'll look at the bln
creatinine ratio briefly here we don't
use it that much
mostly because Bo and cratan both have a
wide normal range so the ratio isn't
that consistent you might see a GFR so
glomerular filtration rate four times
below normal before you'll even notice a
change in the Bo and cratan ratio so we
use it it's used I should say in humans
but
we don't use it that much in animals
they can be used to assess patient
status during treatment so if we have a
baseline and we have a hospitalized
animal and we need to recheck a
bloodwork periodically say it's being
hospitalized for chronic renal failure
or something like that you know
certainly we can use it in those
situations but again not commonly used
you're in protein cratan ratio now this
is interesting it's a quantitative
assessment of renal protein area
basically that means that there's
protein in the urine coming from the
kidney or because of loss of kidney
function so in the absence of
inflammatory cells protein in the urine
does indicate glomerular glomerular
disease so that's kidney disease
essentially how do we test it the most
accurate way would be to do a 24-hour
collection I can't imagine any owner
ever doing that it's tedious errors are
common
it means you would have to for instance
collect your dogs you're in every single
tiny peas within 24 hours it's very very
hard to do that more commonly we do a
mathematical test where we compare the
urine concentration with the creatinine
levels in a single sample it's actually
quite accurate and comprehensive so we
use this you know if we suspect that
there might be protein in the area
coming from the kidneys and we just want
to confirm that it's been validated for
dogs so how do we do it usually we
collect five to ten mils of urine
ideally via systems and cheeses
collected between 10 and 10 a.m. and 2
p.m. it just it's the best time the most
accurate sample we centrifuge it we use
the supernatant then obtain the protein
and creatinine from the sample this is
done in a reference laboratory usually
by the way and then we get the ratio
healthy dogs it should be less than 1
between 1 and 5 we have either pre renal
or functional origin of the protein
protein area if it's greater than 5 we
can say yeah we have renal disease
creating clearance tests another one
here would be a water deprivation test
this is not commonly done and it's
usually done two to screen for diabetes
insipidus so we'll talk about that in
another lecture but if we're suspicious
about the kidneys we could potentially
do a water deprivation test we basically
induced dehydration and just check to
make sure that the kidneys are able to
concentrate urine properly it's
controversial like I say and and again
I've only ever used it today to try to
diagnose diabetes insipidus not for
kidney potential kidney failure if you
feel like it pause the video read
through this it tells you how to do a
water water deprivation test not to say
I've never done one but again not
commonly used let's have a quick look at
what we've talked about with kidneys so
they play a major role in homeostasis
our primary serum chemistry for kidney
function is going to be our Bo n in
cracking urea is the principal end
product of amino acid breakdown so
basically protein breakdown dehydration
increases urea retention so we can get
increased urea with dehydration any
condition that alters the glomerular
filtration rate will alter serum
creatinine levels and something that
wasn't actually mentioned but I'll
mention it now Dalmatian dogs have a
defect and they actually excrete uric
acid which is what birds excrete so
interesting uric acid is an end product
of nitrogen metabolism in birds as I
just mentioned
so that's kidneys let's talk about the
pancreas here very interesting organ the
pancreas is actually two organs in one
they've got that you've got the exocrine
pancreas and the endocrine pancreas of
they're held together in one stroma or
body
the axe and exocrine pancreas is also
called the acid or pancreas it's the
biggest part of the pancreas it's got an
enzyme rich juice and that contains
enzymes for digestion in the small
intestine so that's trypsin amylase
lipase primarily and cells in the
endocrine pancreatic tissue are in
little islands they're called the islets
of langerhans we've got alpha beta gamma
and PP cells in the endocrine pancreas
pancreas so approximately 80 percents of
islets are beta and they decrease
insulin about 29 or asked about a lot of
screen we click on both immediately
primary amine but it's also like an
activity a lot and it was a real idea
these door was tea as an expensive
little way really has strength I gotta
crush everyone the way he snap up time
is remaining
you
emily is for the paper residence oliver
and in the so of course it's her little
tricky the most it's because these
especial so have a pays at the same time
unfamiliar you really really really with
having survived disease so always
propriety of disease what Emily's does
is it breaks down starches in glycogen
in in sugars and you can actually get
increased levels of amylase in the blood
during acute pancreatitis of course or
flare-ups of chronic pancreatitis or if
there are obstructions of the pancreatic
ducts
you
lipase most of it again comes from the
pancreas it breaks down long-chain fatty
acids of lipids so it's responsible for
fat digestion essentially access lipids
are filtered through the kidneys so
levels are normal and early stages of
disease as the disease progresses cells
are replaced with connective tissue
cannot produce lipase and gradually we
had a decrease actually of both amylase
and lipase so a noise in lipase as you
can imagine I've kind of fallen out of
favor a little bit when we're looking at
pancreatic enzymes to try to determine
whether we have pancreatitis for
instance because again lipase gets
eliminated through the kidneys a lot of
times we don't see it going up when
there's pancreatic disease amylase
sometimes doesn't go up in response to
pancreatitis in the way that it should
or sometimes it it's way higher than you
know it should be so it's anchor sorry
emily's and lipase are kind of you know
they can be useful but we don't use them
a lot to look at pancreas anymore so tli
is a radio immunoassay that uses
antibodies to trypsin don't worry so
much about that but no it detects
trypsinogen and trypsin this is
important because trypsinogen is
produced only in the pancreas so this is
a pancreas specific test when the
pancreas is injured trypsinogen is
released in the extracellular space and
convert it to trypsin and that gets it
to the bloodstream so really a great
test to be specific to the pancreas it's
only available for dogs and cats though
and if we can actually use it to look
for pancreatic cancer so as mentioned
trypsin as a proteolytic enzyme that
aids in digestion as are those things
that come out of the exocrine pancreas
it breaks down proteins and foods it's
more readily detectable in feces than in
blood so we can do fecal analysis for
trypsin it should be there if it's not
there that's abnormal
and this is done in reference
laboratories PLI serum feline pancreatic
lipase our canine pancreatic lipase I
mean what we like tippity so that's SP
Li and Cpl I these are great these are
specific for pancreatitis and as I
mentioned before we can use them as a
snack test so we use them regularly in
practice to diagnose pancreatitis and I
don't know what we did before we had
these snap does because it used to be
that we had to send away samples for the
PLI tests and it would take a day or two
to get the results back by which time if
we hadn't already started treating for
pancreatitis then the animal was in dire
straits and and if we had then the
animal was usually better by the time we
got results so you're a snap FPL is the
CPL is it going to be kind of your best
friends in pancreatitis cases of course
also has several tests available most
commonly just your plain old blood
glucose also Josephine glycosylated
hemoglobin and there are some other
routine tests that we do that provide
useful information on the pancreas and
those would be like urinalysis serum
cholesterol triglycerides those sorts of
things so glucose the regulation of
glucose is complex I'm not going to go
into it frankly not really
glucagon thyroxine girl's hormone
epinephrine glucocorticoids these all in
fluids hyperglycemia they all boosts
blood glucose levels right so very
complex insulin however is in
hypoglycemic hormone so it promotes the
glucose flux into its target cells what
does that mean it means that insulin
basically helps sugar or glucose get
into the cells so out of the bloodstream
into the cells pancreatic islets respond
directly to blood glucose concentration
so if the blood glucose goes up
then the it'll produce more insulin so
the pancreatic islets produce more
insulin if the blood glucose goes down
then the pancreas can secrete glucagon
and glucagon stimulates glucose release
from cells so basically the pancreas the
endocrine pancreas is responsible for
controlling blood glucose levels in
various situations remember the only
insulin can lower blood glucose levels
so when we're talking pancreas
hypofunction of the pancreas is your
diabetes mellitus hyperfunction of
endocrine pancreas is hyperinsulinism I
would say I've only seen that with
insulin ones
so basically insulin-secreting tumors
glucose is used to measure pancreatic
function yes in conjunction with other
things we it's great to get test samples
for glucose from a fasted animal a lot
of times you can't glucose drops 10% an
hour once you've collected the sample
it's left in contact with red blood
cells at room temperature so if you
collect it and you leave it on the
counter for several hours and then you
test it and the blood sugar is you know
low well that would be why test it right
away the anticoagulant of choice to use
if you're looking to do a glucose test
the sodium fluoride it doesn't interfere
with the glucose it doesn't degrade it
or anything like that
fructosamine is really great tests for
those fractious diabetic cats glucose
binds to a variety of structures and for
Kosovan as a measurement of the
irreversible reaction of glucose that's
bound to protein so albumin increased
glucose levels so basically an animal
diabetes mellitus will have increased
binding of glucose this makes sense so
increase for toe sameen indicates
persist the type of leukemia
so fructosamine will measure basically
what the blood sugar has been doing over
the last you know 10 to 14 days is kind
of amazing
like that so what have we learned about
the pancreas we know that has a cenar
and endocrine functions the acinar
functions are typically measured on your
routine serum biochemistry by Emily's
and lipase which of course we've talked
about as being maybe not the ideal tests
but they are useful sometimes for
screening tests there are immunologic
tests available as well so this would be
your t lis and your PL is very handy
endocrine functions so those are
measured usually usually with um using
glucose or blood glucose and fructose
amine the use of glucose in the body
remember depends on the amount of
insulin and glucagon that's produced by
the pancreas very important to remember
that serum or plasma has to be separated
from red blood cells immediately after
collection otherwise what happens the
glucose gets used up by those red blood
cells so it decreases about 10 percent
per hour and that's sitting there on the
counter waiting to be run don't wait so
sodium fluoride is the anticoagulant of
choice for those just another note if I
am sending a sample away to a lab for
analysis a lot of times I will do a
quick glucometer reading before I send
it away so that I know what the glucose
was when I first took that sample
certainly I will do that in cases where
I'm suspecting say diabetes or some
other pancreatic issue or potentially
liver issue so I will always always run
a quick blood glucose with a glucometer
before I even send it away just so I
have a good reading just so if the
sample does not have time to degrade
alright so that's it for today Thanks