Cataloue Number C-U 7
URINE REAGENT STRIPS
(10
PARAMETER)
Urine Reagent Strips for
Glucose, Bilirubin, Ketone, Specific Gravity, Blood, pH,
Protein, Urobilinogen, Nitrite and Leukocytes.
INTENDED USE:
C-U 7 for Urinalysis are firm plastic strips to which
are affixed several separate reagent areas.C-U 7 provide
tests for the semi-quantitative determination of
glucose, bilirubin, ketone, specific gravity, blood, pH,
protein, urobilinogen, nitrite and leukocytes in urine.
Test results may provide information regarding the
status of carbohydrate metabolism, kidney and liver
function, acid-base balance, and bacteriurea.1,2
summary and explanation:
The reagent test
areas of urine reagent strips are ready to use upon
removal from the bottle. The entire reagent strip is
disposable. No additional laboratory equipment is
necessary for testing. The directions must be followed
exactly. Accurate timing is essential to provide
optimal results. The reagent strips must be kept in the
bottle with the cap tightly closed (as specified on the
bottle) to maintain reagent reactivity. To obtain
optimal results, it is necessary to use fresh,
well-mixed, and uncentrifuged urine.
TEST PRINCIPLES:
Glucose:
This test is based on a double sequential enzyme
reaction. One enzyme, glucose oxidase, catalyzes the
formation of gluconic acid and hydrogen peroxide from
the oxidation of glucose. A second enzyme, peroxidase,
catalyzes the reaction of hydrogen peroxide with a
potassium iodide chromogen to oxidize the chromogen to
colors ranging from green to brown.
Bilirubin:
This test is based on the coupling of bilirubin with
diazotized dichloroaniline in a strongly acid medium.
Ketone:
This test
is based on the reaction between acetoacetic acid with
nitroprusside. The colors range from buff-pink, for a
"Negative" reading to purple.
Specific Gravity:
This test is based on the release of protons from a
polyacid in the presence of cations in the test liquid.
A colored reaction is produced when the protons released
change the indicator bromthymol blue from blue to
blue-green to yellow.
Blood:
This test
is based on the peroxidase-like activity of hemoglobin
which catalyzes the reaction of cumene-hydroperoxide and
3,3',5,5' tetramethylbenzidine. The resulting color
ranges from orange through green to dark blue.
pH:
This test is based on a double indicator principle that
gives a broad range of colors covering the entire
urinary pH range. Colors range from orange through
yellow and green to blue.
Protein:
This test
is based on the protein error-of-indicators principle.
At a constant pH, the development of any green color is
due to the presence of protein. Colors range from
yellow for "Negative" through yellow-green and green to
green-blue for "Positive" reactions.
Urobilinogen:
This tests is based on a modified Ehrlich reaction in
which p-diethylaminobenzaldehyde reacts with
urobilinogen in a strong acid medium to produce a pink
color.
Nitrite:
This test depends upon the conversion of nitrate to
nitrite by the action of gram negative bacteria in the
urine. The nitrite reacts with p-Arsanilic acid to form
a diazonium compound in acid medium. The diazonium
compound in turn couples with
1,2,3,4-tetrahydrobenzo(h)quinolin to produce a pink
color.
Leukocytes:
This test is based on the action of esterase present in
leukocytes, which catalizes the hydrolysis of an
naphthyl ester derivative. The naphthyl liberated
reacts with a diazonium salt to produce a beige-pink to
purple color.
REAGENTS:
(Based on
dry weight at time of impregnation)
Glucose:
16.3% w/w
glucose oxidase (Aspergillus niger, 1.3 IU); 0.6% w/w
peroxidase (Horseradish, 3300 IU); 7.0% w/w of potassium
iodide; 76.1% w/w buffer and nonreactive ingredients.
Bilirubin:
0.4% w/w
2,4-dichloroaniline diazonium salt, balanced with buffer
and nonreactive ingredients
Specific Gravity:
2.8%
w/w bromthymol blue; 1.2% polyacid; 96.0% nonreactive
ingredients.
Ketone:
7.1% w/w
sodium nitroprusside buffer balanced with buffer and
nonreactive ingredients.
Blood:
22.5% w/w
cumene hydroperoxide, balanced with buffer and
nonreactive ingredients
pH:
0.2% w/w methyl
red; 2.8% w/w bromthymol blue; 97% w/w nonreactive
ingredients.
Protein:
0.3% w/w
tetrabromphenol blue; 99.7% w/w buffer and nonreactive
ingredients.
Urobilinogen:
2.9% w/w p-diethylaminobenzaldehyde, balanced with
buffer and nonreactive ingredients
Nitrite:
1.4% w/w
p-Arsanilic acid, balanced with buffer and nonreactive
ingredients.
Leukocytes:
0.4% derivative of naphthyl ester; 0.2% w/w diazonium
salt; 99.4% buffer and nonreactive ingredients.
WARNINGS AND
PRECAUTIONS:
Urine reagent strips are for in vitro
diagnostic use.
STORAGE:
Store at
temperature between 15 - 30°C (59 - 86° F) and out of
direct sunlight. Do not use after expiration date.
RECOMMENDED
HANDLING PROCEDURES:
All unused strips must
remain in the original bottle. Transfer to any other
container may cause reagent strips to deteriorate and
become nonreactive. Do not remove desiccant(s) from
bottle.
SPECIMEN COLLECTION
AND PREPARATION:
Collect urine in a clean container
according to NCCLS GP16-T guideline and test as soon as
possible. If testing cannot be done within an hour
after voiding, refrigerate the specimen immediately and
let it return to room temperature before testing.
Prolonged exposure of unpreserved urine to room
temperature may result in microbial proliferation with
resultant changes in pH. A shift to alkaline pH may
cause false positive results with the protein test
area. Urine containing glucose may decrease in pH as
organisms metabolize the glucose.
Contamination of the
urine specimen with skin cleansers containing
chlorhexidine may affect protein test results. The user
should determine whether the use of such skin cleanser
is warranted.
MATERIALS PROVIDED:
1. 1 bottle
containing 100 strips of C-U 7.
2. A visual color
chart for reading results is printed on the bottle.
MATERIALS REQUIRED
BUT NOT PROVIDED:
1. A timer capable of
reading accurately in seconds.
2. It is also
recommended that commercial control products be used
for quality
control checks.
PROCEDURE: MUST BE
FOLLOWED EXACTLY TO ACHIEVE RELIABLE TEST RESULTS.
1. Remove one
strip from bottle and close the cap immediately.
Completely immerse reagent areas of the strip in FRESH
urine and remove immediately to avoid dissolving out of
reagents.
2. While removing,
run the edge of the strip against the rim of the urine
container to remove excess urine. Hold the strip in a
horizontal position and bring the edge of the strip into
contact with an absorbent material (paper towel) to
prevent possible mixing of chemicals from adjacent
reagent areas and/or soiling of hands with urine.
3. Compare reagent
areas to corresponding color chart on the bottle label
at the time specified. HOLD STRIP CLOSE TO COLOR BLOCKS
AND MATCH CAREFULLY.
4. Do not use the
same urine sample or control more than once. Always
test with fresh sample.
QUALITY
CONTROL: For best results, performance of reagent
strips should be confirmed by testing known negative and
positive specimens or control whenever a new test is
performed or whenever a new bottle is first opened.
Negative and positive specimens or controls may also be
randomly hidden in each batch of specimens tested. Each
laboratory should establish its own goals for adequate
standards of performance, and should question handling
and testing procedures if these standards are not met.
RESULTS:
Results are obtained by direct comparison of the color
blocks printed on the bottle label. The color blocks
values represent nominal values; actual values will vary
around the nominal values.
LIMITATIONS OF
PROCEDURE:
Glucose:
Large
amounts of ketone bodies (50 mg/dL or greater) may
decrease color development. However, it is unlikely
that the presence of ketones simultaneously with glucose
in the urine is sufficient to produce false negative
results. At glucose levels of 1 g/dL or greater, the
color may appear somewhat mottled. The darkest color
should be used in interpreting results with the color
chart. The reactivity of the glucose test decreases as
the SG of the urine increases. Reactivity may also vary
with temperature.3
Bilirubin:
Reactions
may occur with urine specimens containing large doses of
chlorpromazine or rafampen which might be mistaken for
positive bilirubin.3
Indican (indoxyl sulfate) and metabolites of
Lodinesymbol
226 \f "Symbol" may
cause false positive or atypical color; ascorbic acid
(25 mg/dL or greater) may cause false negatives.
Ketone:
Color
reaction that could be interpreted as "positive" may be
obtained with urine specimens containing MESNA or large
amounts of phenylketones or L-dopa metabolites.3
Specific Gravity:
The
chemical nature of the specific gravity test may cause
slightly different results from those obtained with
other specific gravity methods when elevated amounts of
certain urine constituents are present.
Highly buffered
alkaline urines may cause low readings relative to other
methods. Elevated specific gravity readings may be
obtained in the presence of moderate quantities
(100-750 mg/dL) of protein. Acidic urines (pH 5 or
below) may cause elevated results.
Blood:
The
sensitivity of the blood test is reduced in urine with
high specific gravity and/or high ascorbic acid
content. Microbial peroxidase, associated with urinary
tract infection, may cause a false positive reaction.
pH:
If proper procedure is not followed and excess urine
remains on the strip, a phenomenon known as "runover"
may occur, in which the acid buffer from the protein
reagent will run onto the pH area, causing a false
lowering in the pH result.
Protein:
False
positive results may be obtained with highly buffered or
alkaline urine. Contamination of the urine specimen
with quaternary ammonium compounds may also produce
false positive results.
Urobilinogen:
The
test area will react with interfering substances known
to react with Ehrlich's reagent, such as porphobilinogen
and p-aminosalicylic acid.3
The test is not a reliable method for the detection of
porphobilinogen. Drugs containing azo-dyes (e.g., Azo
Gantrisin) may give a masking golden color. The absence
of urobilinogen cannot be determined with the product.
Nitrite Test:
The
pink color is not quantitative in relation to the number
of bacteria present. Any degree of pink coloration
should be interpreted as a positive nitrite test
suggestive of 105
or more organisms/ml. There are occasional urinary
tract infections from organisms which do not contain
reductase to convert nitrate to nitrite.
Leukocytes:
Highly
colored urine and the presence of the drugs cephalexin
(Keflex®) and
gentamicin have been found to interfere with this test.
High urinary protein of 500mg/dL or above diminish the
intensity of the reaction color. Elevated glucose
concentration or high specific gravity may caused
decreased test results.
EXPECTED VALUES:
Glucose:
Small
amount of glucose are normally excreted by the kidney.5
Concentrations of as little as 0.1 g/dL glucose, read
either at 10 or 30 seconds, may be significantly
abnormal if found consistently. At 10 seconds, results
should be interpreted qualitatively; i.e., negative or
positive. for quantitative results, read at 30 seconds
only.
Bilirubin:
Normally
no bilirubin is detectable in urine by even the most
sensitive methods. Even trace amounts of bilirubin are
sufficiently abnormal to require further investigation.
Atypical colors (colors produced which are different
than the negative or positive color blocks shown on the
Color Chart) may indicate that bilirubin derived bile
pigments are present in the urine sample and are
possibly masking the bilirubin reaction.
Ketone:
Normally no
ketones are present in urine. Detectable levels of
ketone may occur in urine during physiological stress
conditions such as fasting, pregnancy, and frequent
strenuous exercise.6-8
In starvation
diets, or in other abnormal carbohydrate metabolism
situation, ketones appear in the urine in excessively
large amounts before serum ketones are elevated.10
Specific Gravity:
Random urines may vary in specific gravity from
1.003-1.040+. Twenty-four hour urines from normal
adults with normal diets and normal fluid intake will
have a specific gravity of 1.016-1.022.9
In severe renal damage
the specific gravity is fixed at 1.010, the value of the
glomerular filtrate.
Blood:
Any green
spots or green color developing on the reagent area
within 40 seconds is significant and the urine should be
examined further. Blood is frequently, but not
invariably, found in the urine of menstruating females.
pH:3
newborn: 5 - 7 thereafter: 4.5 -
8 average: 6
Protein:
In 24 hours urine, 1-14 mg of protein in 1 dL of urine
may be excreted by the normal kidney.4 A
color matching any block greater than Trace indicated
significant proteinuria. For urine of high specific
gravity, the test area may most closely match the trace
color block even though only normal concentrations of
protein are present. Clinical judgement is needed to
evaluate the significance of trace results.
Urobilinogen:
In a healthy population, the normal urine urobilinogen
range obtained with this test is 0.2 to 1.0 Ehrlich unit
per dL. A result of 2.0 EU/dL may be of clinical
significance and the same patient sample should be
evaluated further.
Nitrite:
Normally no
detectable amount of nitrite is present in urine.3
The nitrite area will be positive in a proportion of
cases of significant infection, depending on how long
the urine specimens were retained in the bladder prior
to collection. Retrieval of positive cases with the
nitrite test range from as low as 40% in instances where
little bladder incubation occurred, to as high as
approximately 80% in instances where a minimum of 4
hours incubation occurred.
Leukocytes:
Normal urine specimens generally yield negative results
with this test. A trace result may be of questionable
clinical significance and it is recommended that the
test be repeated using a fresh sample from the same
patient. Repeated trace and positive results are of
clinical significance.
SPECIFIC
PERFORMANCE CHARACTERISTICS:
The performance
characteristics of C-U 7 urine reagent strips have been
determined both in the laboratory and in clinical
tests. Parameters of importance to the user are
sensitivity, specificity, accuracy and precision.
Generally, this test has been developed to be specific
for the constituent to be measured with the exception of
interferences listed previously (see LIMITATIONS OF
PROCEDURE).
For visually read
strips, accuracy is a function of the manner in which
the color blocks on the bottle label are determined and
the discrimination of the human eye in reading the
test. Precision is difficult to assess in a test of
this type because of the variability of the human eye.
It is for this reason that users are encouraged to
develop their own standards of performance.
Sensitivity:
Glucose Test:
This reagent test area may be read at 10 seconds for
qualitative results or 30 seconds for quantitative
results. The test is specific for glucose; no substance
excreted in urine other than glucose is known to give a
positive result. The reagent area does not react with
lactose, galactose, fructose, nor reducing metabolites
of drugs; e.g., salicylates and nalidixic acid. This
test may be used to determine whether the reducing
substance found in urine is glucose. Approximately 0.1 g
of glucose per dL or urine is detectable.
Bilirubin Test:
The test has a sensitivity of 0.2 - 0.4 mg
bilirubin/dL. The test is considered specific for
bilirubin in urine.1
Ketone Test:
The ketone test area provides semi-quantitative results
(small, moderate, and large) and reacts with acetoacetic
acid in urine. It does not react with
beta-hydroxybutyric acid or acetone. The reagent area
detects as little as 5 to 10 mg acetoacetic acid per dL
of urine.
Specific Gravity:
The
specific gravity test permits determination of urine
specific gravity between 1.000 and 1.030. In general,
it correlates within 0.005 with values obtained with the
refractive index method.
Blood Test:
At the
time of reagent manufacture, the test when read as
instructed has a sensitivity to free hemoglobin of 0.015
mg/dL or 5 to 10 intact red blood cells/uL in urines
with a specific gravity of 1.005 and ascorbic acid
content of <5mg/dL. The test is slightly more sensitive
to free hemoglobin and myoglobin than to intact
erythrocytes.
pH Test:
The pH test
area permits quantitative differentiation of pH values
to one unit within the range of 5 - 9. pH readings are
not affected by variation in the urinary buffer
concentration.
Protein Test:
Quantitative results are obtained from this test area.
5 to 20 mg of albumin per dL urine may be detected as a
"Trace" result. The test area is more sensitive to
albumin than to globulin, hemoglobin, and mucoprotein; a
negative result, therefore, does not rule out the
presence of these other proteins.
Urobilinogen Test:
This test area gives quantitative results and will
detect urobilinogen in concentrations as low as an
Ehrlich unit/dL in urine. The absence of urobilinogen
in the specimen being tested cannot be determined.
Nitrite test:
At the time of reagent manufacture, the test has a
sensitivity to sodium nitrite of 0.075 mg/dL in urine
having low specific gravity and less than 5 mg/dL
ascorbic acid. Comparison of the reacted reagent area
on a white background may aid in the detection of these
low levels which may otherwise be missed. The test is
specific for nitrite and will not react with any other
substance normally excreted in urine.
Leukocytes:
This test
can detect as low as 10-15 WBC/mL.
This test will not react with erythrocytes or bacteria
common in urine.
BIBLIOGRAPHY:
1. Free, A.H. and
Free, H.M.: Urinalysis, Critical Discipline of Clinical
Science. CRC Crit. Rev. Clin. Lab. Sci. 3(4):
481-531; (1972).
2. Yoder,
J..Adams, E.C., and Free, H.M.: Simultaneous screening
for urinary occult blood, protein, glucose and pH.
Amer. J. Med Tech. 31: 285; (1965).
3. Tietz, N.W.:
Clinical Guide to Laboratory Tests; W.B. Saunders
Company, (1976).
4. Burtis C.A. and
Ashwood E.R.: Tietz Textbook of Clinical Chemistry 2nd.
Ed. 2205; 1994
5. Schersten, B.
and Fritz, H.: Subnormal Levels of Glucose in urine.
JAMA 201:129-132; (1967).
6. McGurry, J.D.:
Lilly Lecture, 1978: New Perspectives in the Regulation
of Ketogenesis. Diabetes 28: 517-523 May, (1978).
7. Williamson,
D.H. Physiological Ketoses, or Why Ketone Bodies?
Postgrad. Med. J. (June Suppl.): 371-375; (1971).
8. Paterson, P. et
al.: Maternal and Fetal Ketone Concentrations in Plasma
and Urine. Lancet: 862-865; April 22, (1967).
9. Henry, J.B. et
al.: Clinical Diagnosis and Management by Laboratory
Methods, 16th ed. Philadelphia: Saunders; 1979:
pp.579-608.
10. Fraser, J.et
al.: Studies with a Simplified Nitroprusside Test for
Ketone Bodies in Urine, Serum, Plasma and Milk. Clin.
Chem. Acta II: 372-378; (1965).
*
Trademarks
Serenium® is
a registered trademark of E.R. Squibb & Sons.
Pyridum®
is a registered trademark of Warner-Chilcott
Laboratories.
Azo Gantrisin® and
Azo Gantanol® are
registered trade marks of Roche Laboratories, Division
of Hoffman-LaRoche, Inc.
Lodine®
is a registered trademark of Wyeth-Ayerst Laboratory.
Macrodantin® and
Furadantin® are
registered trade marks of Norwich-Eaton Pharmaceuticals.
Keflex® is
a registered trademark of Dista Products Company.
Revised:
11/96
