When we manages a diabetic animal, we are administering insulin in order
to bring the blood sugar down, hopefully into the normal range.
Too much insulin can drive the glucose too low, causing hypoglycemia.
If the blood sugar goes too low, the pet may experience weakness,
disorientation and even seizures or coma. During the initial
phases of getting diabetes under control with insulin, we like to have
owners use a simple urine dipstick test to help monitor the
effectiveness of our therapy.
Urine glucose testing is based on the fact that excessive amounts of
glucose in the blood will be filtered by the kidneys into the urine.
Once the amount of glucose in the blood exceeds the renal threshold (180
mg/dL) , glucose is spilled into the urine. The renal threshold is the
level at the kidneys can not "process" any more blood glucose and it
spills into the urine. If the blood glucose is high for an extended
period of time, glucose is usually present in the urine. The amount of
glucose present in the urine depends on how high the blood glucose was,
and how long the blood glucose was high. Therefore we can
get a general feeling for how well the blood sugar has been controlled
based on how much glucose is in the urine. In general, we always
want to have a small amount of glucose in the urine of our diabetic
pets, because if there is no glucose in the urine, we do not know
just how low the blood sugar has been. So if we test a dog
with uncontrolled diabetes, we might find a urine sugar of 2000
mg/dl on the urine dipstick. When we start insulin therapy,
we would expect the glucose level to go down over the first few days.
However, if the urine glucose level goes NEGATIVE, all we know is that
the blood sugar is less than 180mg/dl. It could mean that the
blood sugar was 160 or it could just as easily be 20mg/dl.
You can see that there is a high risk that if the urine glucose is
negative that your pet may have been experiencing hypoglycemia for
some part of the day.
How to use Urine Glucose
Dipsticks.
Urine glucose test strips like the pictures shown below are used. The
test strip has a little test area at the end that is dipped into urine
or held in the urine stream. After a certain amount of time, the color
of the test area is compared to a reference color chart. Bayer makes
several types of urine tests strips. Diastix and
Clinistix test only for urine glucose.
Keto-Diastix test for both glucose and ketones. The Diastix
have more "levels" of glucose measurement than the Clinistix. Follow
the instructions that come with your test strips, and use the reference
color chart on the bottle or box. The picture shown below is just an
example - the colors are NOT to be used to compare your urine test
strip.
The color chart tells you
approximately how much glucose has spilled into your pet's urine.
Note: Different test strip brands use different numbers to indicate the
amount of glucose in the urine. When talking to your vet, it is
important that you are both thinking of the same value. For example a
"1" on one brand of strips may indicate very high urine glucose, while
on another strip a "1" is a low urine glucose. A "trace" amount usually
refers to the first non-negative color patch.
Here is a chart comparing the results you can obtain from Diastix,
Keto-diastix, and Clinistix.
Diastix
glucose |
(%) |
Negative |
1/10 |
1/4 |
1/2 |
1 |
2 |
|
(mg/dL) |
Negative |
100 |
250 |
500 |
1000 |
2000
or more |
Keto-Diastix
Ketone |
(mg/dL) |
Negative |
5 |
15 |
40 |
80 |
160 |
Clinistix
glucose |
no units |
Negative
(pink) |
Light
(reddish) |
Medium
(maroon) |
Dark
(purple) |
might be
referred to as: |
negative |
1 |
2 |
3 |
Accuracy
Urine glucose testing is not necessarily an accurate way of measuring
blood glucose, because some animals may hold their urine for a long time
and the amount of glucose in the urine would only reflect an average
level over that period of time. Pets that urinate more frequently
will have a more accurate reflection of the blood glucose
based on their urine glucose.
What do we use the strips for?
We use the dipsticks to help us prevent hypoglycemia. If your pet
has two negative urine glucose tests in a row, we will probably reduce
the amount of insulin because the blood sugar has remained below
180mg/dl during the entire time the urine was collecting.
This is particularly important during the first few months of insulin
therapy because some pets will become hypoglycemic on standard doses of
insulin.
If you use the Keto-diastix, we
can also get a good idea when the body is very poorly regulated.
Ketones are chemicals which are formed when the body cannot use glucose
for energy. If we see ketones in the urine, it means that we are
not controlling the blood sugar accurately and more important, these
pets are likely to become very sick.
We do not generally use dipsticks
to tell us when to increase insulin. Instead we rely on blood
glucose tests and fructosamine tests to make these decisions.
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