Product Manual

STORAGE: All unused strips must remain in the original bottle. Transfer
to any other container may cause reagent strips to deteriorate and
become unreactive. Store at temperatures between 15°–30°C (59°–86°F).
Do not use the strips after their expiration date. Do not store the bottle in
direct sunlight and do not remove the desiccant from the bottle.
IMPORTANT NOTE: PROTECTION AGAINST EXPOSURE TO LIGHT,
HEAT AND AMBIENT MOISTURE IS MANDATORY TO GUARD
AGAINST ALTERED REAGENT REACTIVITY.
REAGENT PERFORMANCE:
Expected values for the “normal” healthy population and the abnormal
population are listed below for each reagent.
Sensitivities listed for each reagent are the generally detectable levels of
the analytes in contrived urines; however, because of the inherent vari-
ability of clinical urines, lesser concentrations may be detected under cer-
tain conditions. The percentage of clinical specimens correctly detected
as positive increases with analyte concentration.
Performance characteristics are based on clinical and analytical studies
and depend upon several factors: the variability of color perception; the
presence or absence of inhibitory and matrix factors typically found in
urine; and the laboratory conditions in which the product is used (e.g.,
lighting, temperature, and humidity). The strips should be read in good
light, such as fluorescent; do not read in direct sunlight.
Each color block or instrumental result represents a range of values.
Because of specimen and reading variability, specimens with analyte
concentrations that fall between nominal levels may give results at either
level. Results will usually be within one level of the true concentration.
Exact agreement between visual results and instrumental results might
not be found because of the inherent differences between the perception
of the human eye and the optical systems of the instruments.
Limitations given for the reagents include specific substances and con-
ditions that may affect the test results. As with all laboratory tests,
definitive diagnostic or therapeutic decisions should not be based
on any single result or method.
Substances that cause abnormal urine color may affect the readability
of test pads on urinalysis reagent strips. These substances include visi-
ble levels of blood or bilirubin and drugs containing dyes (e.g., Pyridium,
Azo Gantrisin, Azo Gantanol), nitrofurantoin (Macrodantin, Furadantin),
or riboflavin. Levels of ascorbic acid normally found in urine do not inter-
fere with these tests.
PROTEIN:
Expected values: Protein in urine can be the result of urological and
nephrological disorders. In normal urine, less than 150 mg of total protein
is excreted per day (24 hour period) (<15 mg/dL). Clinical proteinuria is
indicated at greater than 500 mg of protein per day (strip result of ≥30
mg/dL). Positive results may also indicate tubular or overflow proteinuria
in the absence of any glomerular abnormality or proteins of renal origin
that may be excreted during infection. Urinary protein excretions can be
temporarily elevated in the absence of renal abnormality by strenuous
exercise, orthostatic proteinuria, dehydration, urinary tract infections, and
acute illness with fever.
1,6-7
Clinical judgment is needed to evaluate the
significance of Trace results.
Sensitivity: 15–30 mg/dL albumin
Performance characteristics: The protein test pad is not specific for a
particular protein, and proteins other than albumin can cause a positive
response. The test is less sensitive to mucoproteins and globulins,
which are generally detected at levels of 60 mg/dL or higher.
8
Limitations: Avisibly bloody urine may cause falsely elevated results.
8
BLOOD:
Expected values: Normally, no hemoglobin is detectable in urine (<0.010
mg/dL or 3 RBC/µL). Occult blood occurs in urine as intact erythrocytes
and hemoglobin, which can occur during urological, nephrological and
bleeding disorders. Small amounts of blood (0.030–0.065 mg/dL or a strip
result of Small) are sufficiently abnormal to require further investigation.
The significance of the Trace reaction may vary among patients, and clin-
ical judgment is required for assessment in an individual case. Blood is
often, but not always, found in the urine of menstruating females.
1,9
Sensitivity: 0.015–0.062 mg/dL hemoglobin
Performance characteristics: The appearance of green spots on the
reacted test pad indicates the presence of intact erythrocytes, while green
color across the entire test pad indicates free hemoglobin. The test is
equally sensitive to myoglobin as to hemoglobin. This test complements
the microscopic examination; a hemoglobin concentration of 0.015–0.062
mg/dL is approximately equivalent to 5–20 intact red blood cells per
microliter.
Limitations: Capoten (captopril) may reduce the sensitivity. Certain oxi-
dizing contaminants, such as hypochlorite, may produce false positive
results. Microbial peroxidase associated with urinary tract infection may
cause a false positive reaction.
LEUKOCYTES:
Expected values: Normal urine specimens generally yield negative
results. An increase in leukocytes (≥ 10 leukocytes/µL) is an indication of
pyuria and is found in nearly all diseases of the kidney and urinary tract;
however, pyuria may often be present in non-infective conditions.
1
A strip
result of Small or greater is a useful indicator of infection. Trace results
may be of questionable clinical significance; however, Trace results ob-
served repeatedly may be clinically significant.
Sensitivity: 5–15 white blood cells/hpf in clinical urine.
Performance characteristics: Leukocyte esterase is a reliable indicator
of leukocytes in urine.
1
A positive reaction (Small or greater) at less than
the 2 minute reading time may be regarded as a positive indication of
leukocytes in urine.
Limitations: Elevated glucose concentrations (≥3 g/dL) may cause
decreased test results. The presence of cephalexin (Keflex), cephalothin
(Keflin), or high concentrations of oxalic acid may also cause decreased
test results. Tetracycline may cause decreased reactivity, and high levels
of the drug may cause a false negative reaction. Positive results may occa-
sionally be due to contamination of the specimen by vaginal discharge.
NITRITE:
Expected values: Normally no nitrite is detectable in urine. Many enteric
gram-negative organisms give positive results when their number is
greater than 10
5
/mL (0.075 mg/dL nitrite ion or greater).
2,9
Sensitivity: 0.06–0.1 mg/dL nitrite ion.
Performance characteristics: The test is specific for nitrite and will not
react with any other substance normally excreted in urine. Nitrite concen-
tration during infection increases with the length of time the urine speci-
men is retained in the bladder prior to collection. A minimum of four hours
of bladder incubation significantly increases the likelihood of obtaining a
positive result.
Limitations: Pink spots or pink edges should not be interpreted as a pos-
itive result. A negative result does not rule out significant bacteriuria. False
negative results may occur with shortened bladder incubation of the urine,
absence of dietary nitrate, or the presence of nonreductive pathological
microbes.
GLUCOSE:
Expected values: Small amounts of glucose (<15 mg/dL or 50 mg/day)
are normally excreted by the kidney. These amounts are usually below the
sensitivity level of this test but on occasion may produce a result between
Negative and 100 mg/dL that is interpreted as a positive result. Results at
the first positive level may be significantly abnormal if found consistently.
2,3
Sensitivity: 75–125 mg/dL glucose
Performance characteristics: The test is specific for glucose; no sub-
stance excreted in urine other than glucose is known to give a positive
result. This test may be used to determine whether the reduc-
ing substance found in urine is glucose. If the color appears somewhat
mottled at the higher glucose concentrations, match the darkest color to
the color blocks.
Limitations: Ketone bodies reduce the sensitivity of the test; moderately
high ketone levels (40 mg/dL) may cause false negatives for specimens
containing small amounts of glucose (75–125 mg/dL) but the combination
of such ketone levels and low glucose levels is metabolically improbable
in screening.
KETONE:
Expected values: Normally, no ketone is detectable in urine (up to
2 mg/dL acetoacetic acid). In ketoacidosis, starvation or with other abnor-
malities of carbohydrate or lipid metabolism, ketones may appear in urine
at levels of 10 mg/dL or higher before serum ketone levels are elevated.
Clinical judgment is needed to determine the significance of Trace re-
sults, which may occur during physiological stress conditions such as
fasting, pregnancy and frequent strenuous exercise.
1
Sensitivity: 5–10 mg/dL acetoacetic acid
Performance characteristics: The test reacts with acetoacetic acid in
urine. It does not react with acetone or β-hydroxybutyric acid.
Limitations: False Trace results may occur with highly pigmented urine
specimens or those containing large amounts of levodopa metabolites.
Compounds such as mesna (2-mercaptoethane sulfonic acid) that contain
sulfhydryl groups may cause false positive results or an atypical color
reaction.