Product Manual

G
lucose: Moderate amounts of ketone bodies (40mg/dL or greater) may
decrease color development in urine containing small amounts of glucose
(75-125 mg/dl). However, such concentration of ketone simultaneously with
such glucose concentration is metabolically improbable in screening. The
r
eactivity of the glucose test decreases as the SG and/or ascorbic acid of
the urine increases. Reactivity may also vary with temperature.
3
Bilirubin: Reactions may occur with urine containing large doses of
c
hlorpromazine or rafampen that might be mistaken for positive bilirubin.
3
I
ndican (indoxyl sulfate) and metabolites of Lodine may cause false
p
ositive or atypical color; ascorbic acid (25mg/dL or greater) may cause
false negative results.
K
etone: Color reaction that could be interpreted as “positive” may be
o
btained with urine specimens containing MESNA or large amounts of
phenylketones or L-dopa metabolites.
3
S
pecic Gravity: The chemical nature of the specic gravity test may
c
ause slightly different results from those obtained with the specic gravity
methods when elevated amounts of certain urine constituents are present.
Highly buffered alkaline urine may cause low readings relative to other
m
ethods. Elevated specic gravity readings may be obtained in the
p
resence of moderate quantities (100-750 mg/dl) of protein.
Blood: The sensitivity of the blood test is reduced in urine with high specic
g
ravity and/or high ascorbic acid content. Microbial peroxidase,
a
ssociated with urinary tract infection may cause false positive reactions.
pH: If proper procedure is not followed and excess urine remains on the
strip, a phenomenon known as “running over” may occur, in which the
a
cid buffer from the protein reagent area run onto the pH area, causing a
f
alse lowering in the pH result.
Protein: False positive results may be obtained with highly alkaline urine.
C
ontamination of the urine specimen with quarternary ammonium
c
ompounds may also produce false positive results.
4
Urobilinogen: The test area will react with interfering substances known
t
o react with Ehrlich’s reagent, such as porphobilinogen and
p
-aminosalicyclic acid.
3
T
his test is not a reliable method for the detection
o
f porphobilinogen. Drugs containing azo-dyes (e.g. Azo Gantrisin) may
give a masking golden color. The absence of urobilinogen cannot be
d
etermined with this test.
Nitrite: The pink color is not quantitative in relation to the number of
bacteria present. Any degree of pink coloration should be interpreted as a
p
ositive nitrite test suggestive of 105 or more organisms/ml. There are
o
ccasional urinary tract infections from organisms, which do not contain
reductase to convert nitrate to nitrite.
L
eukocytes: Highly colored urine and the presence of the drugs cephalexin
(
Keex) and gentamicin have been found to interfere with this test. High
urinary protein of 500 mg/dl or above diminishes the intensity of the
r
eaction color. Elevated glucose concentration or high specic gravity may
cause decreased results.
EXPECTED VALUES
Glucose: Small amounts of glucose are normally excreted by the kidney.
5
C
oncentrations as little as 0.1 g/dl glucose, read either at 10 or 30 seconds,
m
ay be signicantly abnormal if found consistently. At 10 seconds, results
should be interpreted qualitatively; for semi-quantitative results, read at
30 seconds only.
Bilirubin: Normally, no bilirubin is detectable in urine by even the most
sensitive method. Even trace amounts of bilirubin are sufciently 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.
9
Specic Gravity: Random urine may vary in specic gravity from
1.003-1.040+. Twenty-four hour urine from normal adults with normal diets
and normal uid intake will have a specic gravity of 0.016-1.02210 in
severe renal damage the specic gravity is xed at 1.010, the value of the
glomerular ltrate.
Blood: Any green spots or green color developing on the reagent area
within 40 seconds is signicant and the urine should be examined
further. Blood is frequently, but not invariably found in the urine of
menstruating females.
pH: newborn: 5-7 thereafter: 4.5-8 average: 6.
3
Protein: In 24-hour urine, 1-14 mg/dl of protein may be excreted by the
normal kidney.
4
A color matching any color block greater than trace
indicates signicant proteinuria. For urine with high specic 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 signicance of trace results.
Urobilinogen: In a healthy population, the normal urine urobilinogen range
obtained with this test is 0.2-1.0 Ehrlich Unit/dl. A result of 2.0 EU/dl may
be of clinical signicance 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 signicant 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 80% in instances where a minimum of 4 hours
incubation occurred.
L
eukocytes: Normal urine specimens generally yield negative results with
this test. A trace result may be of questionable clinical signicance and it
is recommended that the test be repeated using a fresh sample from the
same patient. Repeated trace and positive results are of
c
linical signicance.
S
PECIFIC PERFORMANCE CHARACTERISTICS
The performance characteristics of Pro Advantage by NDC Urine Reagent
S
trips have been determined both in the laboratory and in clinical tests.
P
arameters of importance to the user are sensitivity, specicity, accuracy,
a
nd precision. Generally, Urine Reagent Strips have been developed to be
specic for the constituent to be measured with the exception of
i
nterferences listed above. (See LIMITATIONS OF PROCEDURE)
F
or 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
t
he human eye in reading the test. Precision is difcult to assess in a test
o
f this type because of the variability of the human eye. It is for this reason
t
hat users are encouraged to develop their own standards of performance.
Glucose: This test is specic for glucose; no substances excreted in urine
o
ther than glucose is known to give a positive result. The reagent area
d
oes not react with lactose, galactose, fructose, or reducing metabolites
of drugs; e.g. salicylates and nalidixic acid. This test may be used to
determine whether the reducing substances found in urine is glucose.
A
pproximately 100 mg/dl glucose in urine is detectable.
Bilirubin: The test has a sensitivity of 0.4-0.8 mg/dl bilirubin in urine. The
test is considered specic for bilirubin in urine.
Ketone: The ketone test area provides semi-quantitative results and reacts
with acetoacetic acid in urine. This test does not react with beta-
hydroxybutyric acid or acetone. The reagent area detects as little as 5-10
m
g/dl acetoacetic acid in urine.
Specic Gravity: The specic gravity test permits determination of urine
s
pecic gravity between 1.000 and 1.030. In general, the specic gravity
t
est correlates within 0.005 with values obtained with the reective index
m
ethod.
Blood: At the time of reagent manufacture, this test when read as
i
nstructed has sensitivity to free hemoglobin of 0.015 mg/dl or 5-10 intact
r
ed blood cells/μL urine. This test is slightly more sensitive to free
hemoglobin and myoglobin than to intact erythrocytes.
p
H: The pH test area permits quantitative differentiation of pH values to
o
ne unit within the range of 5-9. pH reading is not affected by variation in
the urinary buffer concentration.
P
rotein: The test area is more sensitive to albumin than to globulin,
h
emoglobin, Bence-Jones proteins, and mucoprotein; a negative result
does not rule out the presence of these other proteins. The test area is
s
ensitive to 15 mg/dl albumin. Depending on the inherent variability in
clinical urine lesser concentration may be detected under certain
c
onditions.
Urobilinogen: This test will detect urobilinogen in concentrations as low
as 0.2 EU/dl in urine. The absence of urobilinogen in the specimen being
t
ested cannot be determined with this test.
Nitrite: At the time of reagent manufacture, this test has sensitivity to
sodium nitrite of 0.075 mg/dl. Comparison of the reacted reagent area on a
white background may aid in the detection of low levels of nitrite ion, which
may otherwise be missed. This test is specic for nitrite and will not react
with substances normally excreted in the urine.
Leukocytes: This test can detect as low as 10-15 WBC/μL. 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. Shchersten, B. and Fritz, H.: Subnormal Levels of Glucose in Urine.
JAMA 201:129-132; (1967).
6. McGarry, 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. Fraser, J. et al.: Studies with a Simplied Nitroprusside Test for Ketone
Bodies in Urine, Serum, Plasma and Milk. Clin. Chem. Acta II:
372-378; (1965).
10. Henry, J.B. et al.: Clinical Diagnosis and Management by Laboratory
Methods, 16th Ed. Philadelphia: Saunders; (1979).
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