refractometer
Give this one a try later!
A "manual" specific gravity performed on a refractometer is typically the
"back up" method to the dipstick.
. The refractometer method is based on the "refractive index of light" theory
- see page 76 in Brunzel.
As increased numbers of solute particles are present in the urine sample
more light is refracted hence giving a higher specific gravity reading. See
figure 5-4 on page 76 for a schematic of the refractometer and see figure
5-6 on page 77 for a view of the reading scale within the refractometer.
specific gravity
Give this one a try later!
, expression of concentration" of dissolved solute particles.
The typical range of measurement for SG on the dipstick is from 1.000 to
1.030.
Remember, it is "physiologically impossible" for a patient to have a S.G. of
1.000. (1.000 is the SG of distilled water).
An increased specific gravity can be found in urine samples with increased
concentrations of substances such as glucose, protein or urea.
Decreased specific gravities are found in more dilute urine and a particular
disease that commonly has a low S.G. is Diabetes insipidus
A consistent urine S.G. of 1.010 is significant since this is the specific gravity
of the "ultrafiltrate" which is protein free!
What would the final refractometer S.G. be if a reading of 1.019 was obtained from a
1/2 urine dilution?
Give this one a try later!
Two things first.
Notice that S.G. results do not have "units" such as grams or liters etc. and in
the case of a urine dilution you must take ONLY the last 2 numbers in the
S.G. reading and multiply by the dilution factor to get the final specific
gravity result.
In this example the final S.G. is 1.038 (1.019 times the dilution factor of 2 =
1.038)
,collection techniques
Give this one a try later!
routine void
midstream clean catch
catheterized specimen
suprapubic aspiration
collection bag
catheterized specimen
Give this one a try later!
Catheterization is a procedure performed by a physician or nurse where a
sterile tube is inserted into the bladder.
Urine is collected in this way if the patient has trouble voiding or if a
suitable specimen cannot be obtained.
The urine specimen may be used for routine screening, bacterial culture or
cytological exam (observe for cancer cells).
bacteria and uti
Give this one a try later!
, Urinary tract infections can involve the bladder (cystitis), the renal pelvis
and tubules (pyelonephritis), or both."
The way a UTI develops is either through "the localization of bacteria:
"up the urethra into the bladder" - this is known as an "ascending infection"
or
"from the bloodstream into the kidney and urinary tract"
Normally the urine and bladder are sterile.
However, in conditions of urinary obstruction, bladder dysfunction, urine
stasis (stagnation or non movement) or even catheterization bacteria may
be introduced and a urinary tract infection results.
Note: The presence of bacteria on a urine microscopic exam may also be
due to bacterial contamination in the specimen collection process.
Typically, the presence of "both" bacteria and WBC rules out contamination
as the cause.
chemical tests
Give this one a try later!
specific gravity
pH
blood
leukocyte esterase
nitrite
protein
glucose
ketones
Give this one a try later!
A "manual" specific gravity performed on a refractometer is typically the
"back up" method to the dipstick.
. The refractometer method is based on the "refractive index of light" theory
- see page 76 in Brunzel.
As increased numbers of solute particles are present in the urine sample
more light is refracted hence giving a higher specific gravity reading. See
figure 5-4 on page 76 for a schematic of the refractometer and see figure
5-6 on page 77 for a view of the reading scale within the refractometer.
specific gravity
Give this one a try later!
, expression of concentration" of dissolved solute particles.
The typical range of measurement for SG on the dipstick is from 1.000 to
1.030.
Remember, it is "physiologically impossible" for a patient to have a S.G. of
1.000. (1.000 is the SG of distilled water).
An increased specific gravity can be found in urine samples with increased
concentrations of substances such as glucose, protein or urea.
Decreased specific gravities are found in more dilute urine and a particular
disease that commonly has a low S.G. is Diabetes insipidus
A consistent urine S.G. of 1.010 is significant since this is the specific gravity
of the "ultrafiltrate" which is protein free!
What would the final refractometer S.G. be if a reading of 1.019 was obtained from a
1/2 urine dilution?
Give this one a try later!
Two things first.
Notice that S.G. results do not have "units" such as grams or liters etc. and in
the case of a urine dilution you must take ONLY the last 2 numbers in the
S.G. reading and multiply by the dilution factor to get the final specific
gravity result.
In this example the final S.G. is 1.038 (1.019 times the dilution factor of 2 =
1.038)
,collection techniques
Give this one a try later!
routine void
midstream clean catch
catheterized specimen
suprapubic aspiration
collection bag
catheterized specimen
Give this one a try later!
Catheterization is a procedure performed by a physician or nurse where a
sterile tube is inserted into the bladder.
Urine is collected in this way if the patient has trouble voiding or if a
suitable specimen cannot be obtained.
The urine specimen may be used for routine screening, bacterial culture or
cytological exam (observe for cancer cells).
bacteria and uti
Give this one a try later!
, Urinary tract infections can involve the bladder (cystitis), the renal pelvis
and tubules (pyelonephritis), or both."
The way a UTI develops is either through "the localization of bacteria:
"up the urethra into the bladder" - this is known as an "ascending infection"
or
"from the bloodstream into the kidney and urinary tract"
Normally the urine and bladder are sterile.
However, in conditions of urinary obstruction, bladder dysfunction, urine
stasis (stagnation or non movement) or even catheterization bacteria may
be introduced and a urinary tract infection results.
Note: The presence of bacteria on a urine microscopic exam may also be
due to bacterial contamination in the specimen collection process.
Typically, the presence of "both" bacteria and WBC rules out contamination
as the cause.
chemical tests
Give this one a try later!
specific gravity
pH
blood
leukocyte esterase
nitrite
protein
glucose
ketones
