a number of tests which can be run on a urine sample. Collectively these
tests are known as urinalysis.
test can help with the diagnosis of CKD, and may be useful for detecting
early CKD before it begins to show in blood tests.
(urine protein to creatinine ratio) test can give some idea of the
severity of the CKD.
tests are also very important for helping to diagnose kidney and urinary
What is Urinalysis?
Urinalysis is the term used to refer to a series of tests run on a urine
sample. These tests can
help to confirm the CKD diagnosis, or may give an early warning of CKD. They are also used
to check for imbalances and infections.
Urine samples may be obtained in a number of ways.
Some methods (free catch and non-absorbent litter) can be used at home and
you then take the sample to your vet for testing. Samples obtained in
this way are sufficient to run most of the tests discussed here, but are not sterile,
so are not suitable for running a culture and sensitivity test (see
below) to check
for infection. In this situation, ideally you need to take your cat to your vet
If you do obtain a sample at home, ideally you want to take it to the vet
within four hours. If you are assessing the urine for the presence of
crystals, you need to take it in sooner:
Effects of storage time and temperature on pH,
specific gravity, and crystal formation in urine samples from dogs and
cats (2003) Albasan H,
Lulich JP, Osborne CA, Lekcharoensuk C, Ulrich LK & Carpenter KA
Journal of the American Veterinary Medical Association222(2)
pp176-179 found that "Storage
time and temperature did not have a significant effect on pH or specific
gravity" but "Urine
samples should be analyzed within 60 minutes of collection to minimize
temperature- and time-dependent effects on in vitro crystal formation."
Free catch means that you stick a container under your cat as s/he urinates and catch some urine in
it. I can't imagine my cats tolerating this but some people's cats don't mind,
in which case it is probably the quickest and easiest way.
Some people use a ladle, which means you don't need to
get too close to your cat. You can also buy sterile, individually
wrapped cups for this purpose from your vet or online. As with humans, you
should aim for a mid stream sample, i.e. let your cat urinate for a few
seconds before putting the cup in place. To maintain sterility, try not to
let the cup touch anything, such as your cat or the litter tray.
sell a sterile urine catcher called the Urikone which costs £69.60
Non-absorbent litter is made of non-absorbent
granules. You put it in the litter tray in place of normal litter, and since
it does not absorb liquids, you can scoop up some urine to take to the vet.
My vet sells the Smart Cat Urine Test Kit for £2 a packet.
My cats like a lot of litter, so I use two bags, but some people do only use one bag.
This is a one use only kit.
is one brand which can be washed and re-used.
Kit 4 Cat
is another type of non-absorbent litter that is apparently very similar to real
is a non-absorbent litter available in a variety of European countries.
These are litters that change colour when they detect certain things in a
cat's urine, such as blood.
Veterinary Practice News
(2008) explains more about how these products work.
Although these tests can give
you some basic information, e.g. the presence of blood or bacteria, you
should take a urine sample to your vet for proper analysis. The white blood
cell reading in the urine test itself is often inaccurate.
Check Up is a test that
checks for blood in urine, and which may also be used to check for other
issues, such as diabetes.
This is the best way to obtain a sterile sample, which is required in order to
run a culture and sensitivity test to check for infections (see
Cystocentesis means the removal of urine
from the bladder via a fine needle. It sounds far worse than it is, I've
seen this done on my cats and they do not even flinch. It is safe as long
as you have a competent vet, who should use ultrasound to guide the
needle. It is only suitable for a cat who has urine in the bladder, and it
is usually not appropriate for a cat who struggles at the vet's.
The urine specific gravity (USG) test
checks whether the cat is concentrating urine appropriately. Because of
their desert heritage, in normal circumstances healthy cats have
concentrated urine, but CKD cats usually have dilute urine.
A cat's USG level may change quite a lot over the course of
even a day.
Before diagnosing CKD, therefore, the test should be run more than once
and other causes ruled out.
Once a cat is receiving regular fluid therapy, this
test can be rather unreliable.
Using urine specific gravity (2015) Watson
ADJ, Lefebvre HP & Elliott J International Renal Interest Society
has information on the significance of USG in cats.
This test should be run by refractometer -
using the dipstick method is rather unreliable.
Advanced interpretation of the urine dipstick
(2010) Pressler B CVC in Washington DC Proceedings states ""Refractometers are the best balance between cost and accuracy for
measuring urine specific gravity. The best refractometers have different
scales for dogs and cats; however, if these are not available, the
differences are rarely clinically significant. Urine dipsticks are too
inaccurate to be clinically reliable for measurement of specific
Urine Specific Gravity
This is not
actually as simple as it first appears because "normal" depends upon a
number of factors, such as how much a cat is drinking, the weather etc.
USG therefore needs to be considered in conjunction with blood test
results and the cat's overall status.
The typical range for hydrated cats is around 1.035 to 1.060.
A cat with a USG below 1.040 is generally
considered to have a problem of some kind.
In a cat with normal bloodwork, it may be
an early warning sign that CKD is developing.
Most CKD cats have a much lower USG of
between 1.008 and 1.012.
numbers have a decimal place after the 1, vets often say the numbers
verbally in a different way, so for example, a USG of 1.012 would be
referred to as "ten twelve" rather than "one point oh one two."
Urine Specific Gravity
Levels in CKD Cats
A USG level below 1.040 is considered low in cats.
CKD cats have a much lower USG of between 1.008 and 1.012, which is known as isothenuria.
Prolonging life and kidney function
(2007) a paper presented to the 32nd World Small Animal
Veterinary Association Congress by Dr D Chew,explains more
Of course, CKD is never simple, so occasionally a cat will have what
appears to be a normal USG yet have CKD.
Urine specific gravity (2015) Watson
ADJ, Lefebvre HP & Elliott J International Renal Interest Society
states: 'However, USG values in some cats with chronic kidney
disease (CKD) and azotaemia may be as high as 1.040 or 1.045, so kidney
disease could still be suspected in a cat if these values are
accompanied by persistent azotaemia.'
Urine Specific Gravity:
Other Causes When Low
A low USG may also be seen in cats with
the following conditions:
This is a measure of particles
dissolved in solution, and measures the concentration of the urine.
It is usually used in conjunction with USG. The approximate normal range
for urine osmolality is
Serum (blood) measurement of osmolality gives some indication of
hydration levels - a dehydrated cat will often have high osmolality,
over-hydrated cat will usually have low levels. High levels may also
urine sample via cystocentesis (a needle into the bladder) may sometimes cause blood in the urine.
possible causes include
pressure. or, occasionally, cancer. Ollie had this symptom towards the
end, and I think it might have been because of cancer (he had been treated
for cancer a couple of years previously).
vet may wish to test for glucose (sugar) in the urine, particularly if
your cat has high
levels, in order to rule out diabetes.
do not have glucose in their urine.
However, this value may increase suddenly in cats because of stress, for
example in cats who get stressed or frightened at the vet’s.
also be elevated in cats with acute kidney injury.
Overview of feline bloodwork (2008) Jensen A 2008 Zimmer
Feline Foundation states "One way to differentiate between a
glucose spike due to acute stress and high blood glucose due to diabetes
is through urinalysis. If there is no glucose in the urine in the face of
high blood glucose, it may be due to the fact that the blood glucose has
not been high long enough to overflow into the urine, suggesting an acute
spike. This is not definitive, however. Presence of glucose in the urine
is, however, highly suggestive of diabetes."
TREATING YOUR CAT WITHOUT VETERINARY ADVICE CAN BE
tried very hard to ensure that the information provided in this website is
accurate, but I am NOT a vet, just an ordinary person who has lived
through CKD with three cats. This website is for educational purposes
only, and is not intended to be used to diagnose or treat any cat. Before
trying any of the treatments described herein, you MUST consult a
qualified veterinarian and obtain professional advice on the correct
regimen for your cat and his or her particular requirements; and you
should only use any treatments described here with the full knowledge and
approval of your vet. No responsibility can be accepted.
If your cat
appears to be in pain or distress, do not waste time on the internet,
contact your vet immediately.
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You may print
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