Home
Catalogue
Contact
us
Catalogue Number C-U 3
URINE REAGENT
STRIPS
(1 PARAMETER)
Tests for
Protein
intended use:
Urine Reagent Strips (C-U
3) for Urinalysis are firm plastic strips to which protein
reagent areas are affixed. Urine Reagent Strips provide
tests for the semi-quantitative determination of protein in
urine.
SUMMARY:
Test results may provide
information regarding the status of kidney function.1-3
The kidney glomeruli act
as ultrafilters for the plasma protein; however as much as
150 mg/dl of protein may normally be excreted into the
urine. In glomerular proteinuria, an increase in glomerular
permeability occurs, resulting in an increase of urine
proteins. High urine protein concentration therefore may
indicate proteinuria.
CHEMICAL PRINCIPLE OF
THE PROCEDURE:
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.
REAGENTS:
(Based on dry
weight at time of impregnation)
0.3% w/w tetrabromphenol
blue; 99.7% w/w buffer and nonreactive ingredients.
WARNINGS AND
PRECAUTIONS: Urine reagent strips are for in vitro
diagnostic use.
STORAGE:
Store opened and unopened
bottles at a temperature between 15°- 30°C (59°-86° F) and
out of direct sunlight. Do not use after expiration
date. Deterioration rate will be affected by mishandling of
device.
RECOMMENDED PROCEDURES
FOR HANDLING URINE REAGENT STRIPS:
All unused strips must
remain in the original bottle. Transfer to any other
container may cause reagent strips to deteriorate and become
unreactive. Do not remove desiccant(s) from bottle. Replace
cap immediately and tightly after removing reagent strip. Do
not touch test areas of the reagent strip. Work areas and
specimen containers should be free of detergents and other
contamination substances. Dip test areas in urine
completely, but briefly, to avoid dissolving out the
reagents. Read test results carefully, in a good light and
with the test area held near the appropriate Color Chart on
the bottle label.
IMPORTANT:
Protection
against ambient moisture, light and heat is essential to
guard against altered reagent reactivity.
Discoloration or darkening of reagent areas may indicate
deterioration. If this is evident, or if test results are
questionable or inconsistent with expected finding, the
following steps are recommended: (1) confirm that the
product is within the expiration date shown on the label.
(2) check performance against known positive control
materials. (3) retest with fresh product.
SPECIMEN COLLECTION AND
PREPARATION:
Collect urine in a clean
container according to NCCLS GP16-T 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.
Contamination of the urine
specimen with skin cleansers containing chlorhexidine may
affect test results. The user should determine whether
the use of such skin cleansers is warranted.
PROCEDURE: MUST BE
FOLLOWED EXACTLY TO ACHIEVE RELIABLE TEST RESULTS.
1. Collect FRESH
urine specimen in a clean dry container. Mix well
immediately before testing.
2.
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 reagents.
3.
While removing, run the edge of the strip against the rim of
the urine container to remove excess urine.
4. Compare reagent
areas to corresponding color chart on the bottle label at
the time specified. HOLD STRIP CLOSE TO COLOR BLOCKS AND
MATCH CAREFULLY.
This test may be
read at any time up to one minute after dipping.
QUALITY
CONTROL: For best results, performance of reagent
strips should be confirmed by testing known negative and
positive specimens or control daily 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 with C-U 3 are obtained in clinically meaningful
units directly from the Color Chart comparison. The
color blocks represent nominal values; actual values will
vary around the nominal values.
LIMITATIONS OF
PROCEDURE:
As with all laboratory
tests, definitive diagnostic or therapeutic decisions should
not be based on any single result or method. This test is
only for screening; all positive results should be confirmed
by a quantitative method where accuracy and sensitivity are
greater.
Substances that cause
abnormal urine color, such as Serenium®*,
drugs containing azo dyes(e.g.,Pyridium®**,
Azo Gantrisin®***,
AzoGantanol®***),
nitrofurantoin(Macrodantin®†,Furadantin®†),
and riboflavin, may affect the readability of reagent areas
on urinalysis reagent strips.5
The color development on the reagent pad may be masked or a
color reaction may be produced on the pad that could be
interpreted as a false positive.
High blood concentration
in sample may mask color development or cause atypical color
formation. Turbid urine may be used, however reaction must
be observed carefully.
Interpretation of results
will depend upon several factors: the variability of color
perception; the presence or absence of inhibitory factors;
the presence or absence of inhibitory factors typically
found in urine, the specific gravity or the pH; and the
lighting conditions under which the product is used.
False positive results may
be obtained with highly concentrated or alkaline urine.
Contamination of the urine specimen with quaternary ammonium
compounds may also produce false positive results.6
EXPECTED VALUES:
Normal secretion of
protein in the urine is less than 15 mg/dl.4
A color matching any block greater than Trace may indicate
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 judgment is needed to
evaluate the significance of trace results.
PERFORMANCE
CHARACTERISTICS:
Sensitivity:
The following table lists
the generally detectable level of protein in contrived
urine; however, because of the inherent variability of
clinical urines, lesser concentrations may be detected under
certain conditions. Sensitivity will vary depending on the
limitation factors of the test. (see LIMITATIONS OF
PROCEDURE)
Reagent
Area
Sensitivity
Protein
15 mg/dL albumin
Specificity
The reagent area is more
sensitive to albumin than to globulins, hemoglobin,
Bence-Jones Protein and mucoprotein; negative result
does not rule out the presence of these other proteins.
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. Kark, R.M. et al.:
A Primer of Urinalysis, 2nd ed. New York: Harper and Row;
1963.
3. 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.
4. Burtis C.A. and
Ashwood E.R.: Tietz Textbook of Clinical Chemistry 2nd Ed.:
718,1 526; 1994.
5. Tietz, N.W.,
Fundamentals of Clinical Chemistry 2nd ed. W.B. Saunders
Company, 1976.
6. Tietz, N.W.,
Clinical Guide to Laboratory Tests 2nd ed. W.B. Saunders
Company, 1990.
*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.
† Macrodantin® and
Furadantin® are
registered trade marks of Norwich-Eaton Pharmaceuticals
Revised: 8/96
