Message Number: YG4146 | New FHL Archives Search
From: Bruce Williams, DVM
Date: 2001-05-30 23:24:00 UTC
Subject: Re: reference range for USG?

--- In Ferret-Health-list@y..., "Sonya Grable" <sterling_97@e...>
> Hi,
> What is the reference range for urine specific gravity in ferrets?

Dear Sonya:

There is really no traditional "reference range" for specific gravity
in ferrets. The specific gravity is a measur of the concentration of
the solids in urine, and can fluctuate widely based on the hydration
status of the animal at the time that the urine is obtained, as well
as other factors, such as the presence or absence of diabetes,
functional state of the kidney, etc.

The way we look at specific gravity is to see if the animal is able
to exceed a level of 1.030-1.035 - if this is not seen on a routine
catch, then we will take it again, and may even run a limited water
deprivation test to see if we can make it go up over this level. If
it does at any time, for any reason, then you can safely assume that
the kidney can concentrate urine effectively.

Older kidneys, may be able to concentrate to 1.020 or so with out
signs of disease. The problem occurs when the level constantly is at
the 1.008-1.012 range. This is the concentration of the blood that
passes through the kidney, and signifies that the kidney is not able
to concentrate the urine at all. This finding, coupled with evidence
of an elevated BUN, creatine, and or phosphorus, indicate the
presence of renal failure.

A diagnosis of renal failure should always be based on all findings
evaluated in concert - the specific gravity of the urine, the
urinalysis, and the so-call renal enzymes in the blood (actually not
enzymes, but normal substances excreted by the kidney, such as BUN,
creatinine, etc.

With kindest regards,

Bruce H. Williams, DVM, DACVP
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