Chapter 6 Flashcards
(301 cards)
1
Q
Reagent strips provide-
A
a simple, rapid means for performing routine chemical tests on urine
2
Q
The brand and number of tests used are a matter of-
A
laboratory preference
3
Q
reagent strips specified by-
A
urinalysis instrumentation manufacturers
4
Q
reagent Strips consist of-
A
chemical-impregnated absorbent pads on a plastic strip
5
Q
A color-producing chemical reaction takes place when-
A
the absorbent pad comes in contact with urine
6
Q
Several degrees of color are shown to provide semi-quantitative readings of- (6)
A
-negative
-trace
-1+
-2+
-3+
-4+
7
Q
reactions are interpreted by-
A
comparing the color produced on the pad within the required time frame with a chart supplied by the manufacturer
8
Q
Estimates of mg/dL are also provided for-
A
many of the test areas
9
Q
Urine reagent strips- (8)
A
-pH
-Protein
-Glucose
-Ketones
-Blood
-Bilirubin & urobilinogen
-Nitrate & leukocytes
-Specific gravity
10
Q
reagent strip technique- (5)
A
-Dip strip briefly into well-mixed specimen at room temperature
-Remove excess urine by touching edge of strip to container as strip is withdrawn
-Blot edge of strip on absorbent pad
-Wait specified amount of time
-Read using a good light source
11
Q
Formed elements such as red and white blood cells sink to the bottom of the specimen and will be-
A
undetected in an unmixed specimen
12
Q
Allowing the strip to remain in the urine for an extended period may cause-
A
leaching of reagents from the pads
13
Q
Excess urine remaining on the strip after its removal from the specimen can produce a runover between-
A
chemicals on adjacent pads, producing distortion of the colors
14
Q
The timing for reactions to take place varies between-
A
tests and manufacturers; the manufacturer’s stated time should be followed
15
Q
A good light source is essential for accurate interpretation of-
A
color reactions
16
Q
The strip must be held close to the color chart without actually being placed on the chart; reagent strips and color charts from different manufacturers are not-
A
interchangeable
17
Q
Specimens that have been refrigerated must be allowed to-
A
return to room temperature prior to reagent strip testing
18
Q
handling & storing reagent strips- (6)
A
-Store with desiccant in an opaque, tightly sealed container
-Remove strips immediately prior to use
-Do not expose to volatile fumes
-Store below 30°C
-Do not use past the expiration date
-Visually inspect for discoloration/deterioration
19
Q
Run positive and negative controls, usually at-
A
the beginning of a shift
20
Q
Run additional controls
on reagent strips when- (3)
A
-a new bottle of strips is opened
-results are questionable
-there are concerns over strip integrity
21
Q
Do not use distilled water as a negative control because-
A
reactions are designed for urine ionic concentration
22
Q
All negative control readings should be-
A
negative
23
Q
Positive control readings should agree with-
A
published control values
24
Q
Confirmatory tests use different reagents or methodologies to detect-
A
the same substances as reagent strips with the same or greater sensitivity or specificity
25
Non-reagent strip testing procedures using tablets and liquid chemicals may be available when-
questionable results are obtained
26
Chemical reliability of these procedures also must be checked using-
positive & negative controls
27
Based on pKa (dissociation constant) of a-
polyelectrolyte in alkaline medium
28
Polyelectrolyte ionizes releasing H+ in relation to-
concentration of urine
29
a higher concentration of specific gravity in confirmatory tests means-
more H+ released
30
Indicator bromthymol blue measures-
pH change
31
Reagent Strip-Specific Gravity Reaction has no reaction interference from- (3)
-large molecules
-urea & glucose
-radiographic dye & plasma expanders
32
no reaction interference is the reason for-
difference in refractometer reading
33
Confirmatory Testing has a slight elevation of reaction interference from-
protein
34
decreased reaction interference reading- (2)
-Urine pH 6.5 or higher
-Interferes with indicator; add 0.005 to the reading; readers automatically add this
35
Lungs and kidneys are major regulators of-
acid-base content
36
First morning urine pH specimens are-
slightly acidic at 5.0 to 6.0
37
Postprandial urine pH specimen are more-
alkaline
38
normal urine pH range-
4.5 to 8.0
39
no absolute values are assigned in-
urine pH
40
urine pH Considerations include- (5)
-Acid-base content of the blood
-Patient’s renal function
-Presence of a uti
-Patient’s dietary intake
-Age of the specimen
41
Respiratory or metabolic alkalosis urine is-
alkaline
42
urine pH tests treat-
uti's
43
urine pH tests are the Precipitation/identification of-
crystals
44
High-protein diets=
acidic urine
45
Low-protein diets=
alkaline urine
46
Respiratory or metabolic acidosis/ketosis urine is-
acidic
47
A pH above 8.5 is associated with a specimen that-
has been preserved improperly
48
A pH above 8.5 is associated with a specimen that has been preserved improperly and indicates-
that a fresh specimen should be obtained to ensure the validity of testing
49
pH-Reagent Strip Reactions are needed to measure between-
5.0 and 9.0 in one half or one unit increments
50
Double-indicator system reaction- (2)
-Methyl red = 4 to 6 red/orange to yellow
-Bromthymol blue = 6 to 9 green to blue
51
protein is most indicative of-
renal disease
52
Proteinuria seen in-
early renal disease
53
Normal protein reading-
<10 mg/dL or 100 mg/24 h
54
Low-molecular-weight serum proteins are-
filtered; many are reabsorbed
55
primary protein of concern-
albumin
56
Other proteins include- (2)
-Prostatic/seminal/vaginal secretions
-Uromodulin/tamm-horsefall
57
Presence of protein requires determination of-
normal or pathological condition
58
Clinical proteinuria becomes concern when-
30 mg/dL - 300 mg/24 h
59
Variety of causes of proteinuria- (3)
-Prerenal
-Renal
-Postrenal
60
pre renal proteinuria conditions affect-
the plasma, not the kidney
61
pre renal proteinuria isn't indicative of-
renal disease
62
pre renal proteinuria are rarely seen on-
reagent strip (not albumin)
63
Multiple myeloma confirmation- (2)
-serum electrophoresis
-immunoelectrophoresis
64
Screening for BJP is not performed-
routinely
65
Screening Test for Bence Jones Protein (BJP) coagulates between-
40 C & 60 C
66
Screening Test for Bence Jones Protein (BJP) dissolves when-
temp reaches 100 C
67
Specimens suspected of containing BJP appear- (2)
-turbid between 40°C & 60°C
-clear at 100°
68
renal proteinuria, glomerular or tubular damage- (4)
-Glomerular proteinuria
-Microalbuminuria
-Orthostatic (postural) proteinuria
-Tubular proteinuria
69
glomerular proteinuria is damage to-
glomerular membrane
70
Impaired selective filtration causes-
increased protein filtration leading to cellular excretion
71
Abnormal substances deposit on-
membrane
72
Primarily immune disorders result in-
immune complex formation
73
primary immune disorders ex- (4)
-Lupus erythematosus
-glomerulonephritis
-amyloids
-other toxins
74
glomerular proteinuria increased pressure on the filtration mechanism- (4)
-Hypertension
-Strenuous exercise
-Dehydration
-Pregnancy (Preeclampsia)
75
Benign proteinuria (transient)- (4)
-Strenuous exercise
-high fever
-dehydration
-exposure to cold
76
occurs in diabetic nephropathy in people with type 1 & 2 diabetes mellitus- (2)
-microalbuminuria detection
-eventually renal failure
77
believed to account for orthostatic (postural) proteinuria-
Increased pressure on the renal vein when in the vertical position
78
orthostatic (postural) proteinuria occurs-
in vertical position, disappears in horizontal position
79
collection instructions for orthostatic (postural) proteinuria- (2)
-empty bladder before bed
-Collect 1st specimen immediately on arising & collect 2nd specimen after remaining in vertical position for several hours
80
Negative orthostatic (postural) proteinuria reading will be seen on-
first morning specimen
81
positive orthostatic (postural) proteinuria result will be found on-
second specimen
82
tubular damage affecting reabsorptive ability-
tubular dysfunction
83
causes of tubular dysfunction- (4)
-toxic substances
-heavy metals
-viral infections
-fanconi syndrome
84
fanconi syndrome-
generalized proximal convoluted tubule defect
85
amount of protein in urine found in glomerular disorders-
up to 4 g/day
86
amount of protein in urine found in tubular disorders-
much lower levels
87
protein can be added to the urine as it passes through- (2)
-lower urinary tract
-genitourinary tract
88
Microbial infections & inflammations cause release of-
interstitial fluid protein
89
the presence of blood in the urine contributes protein- (2)
-menstrual contamination
-semen/prostatic fluid
90
traditional reagent strip testing for protein uses the principle of-
protein error indicators
91
Certain indicators change color in the presence of-
protein at a constant pH
92
Protein accepts H+ from the indicator because-
increased sensitivity to albumin due to more amino groups to accept H+ than other proteins
93
indicators of reagent strip reactions- (4)
-Tetrabromophenol blue
-tetrachlorophenol
-tetrabromosulfonephthalein
-acid buffer
94
in the absence of protein at a pH level of 3, both indicators appear-
yellow
95
as protein concentration increases, color progresses through-
green to blue
96
negative reagent strip reactions in Postrenal Proteinuria are reported as- (3)
-negative trace
-1+, 2+, 3+, 4+
-30, 100, 300, 2000 mg/dL
97
reagent strip reaction trace values are considered to be-
less than 30 mg/dL
98
Highly buffered alkaline urine overrides acid buffer system causing-
color change unrelated to protein concentration
99
Leaving reagent pad in urine too long removes-
buffer
100
false-positives in postrenal proteinuria occur from- (2)
-Highly pigmented urine
-High SG
101
highly pigmented urine can be caused by-
AZO
102
Sulfosalicylic Acid (SSA) precipitation confirmatory test for-
protein
103
SSA is a Cold precipitation test that reacts equally with-
all forms of protein
104
SSA Precipitation tests Must be performed on centrifuged specimens to-
remove any extraneous contamination
105
Semiquantitative Microalbuminuria testing for-
patients at risk for renal disease
106
Immunochemical assays for- (2)
-albumin
-albumin-specific reagent strips
107
recommended tests for Microalbuminuria-
first morning specimens
108
micral-test reagent strips contain-
gold-labeled antihuman antibody-enzyme conjugate
109
Dip Microalbuminuria test strip in urine to mark level for-
5 seconds
110
albumin in the urine binds to-
the antibody
111
Bound and unbound conjugates move-
up strip
112
Unbound conjugates are removed in captive zone by containing-
albumin
113
bound conjugates continues up-
the strip
114
the conjugate enzyme reacts with the substrate producing colors ranging from-
white (neg) to red (varying deg)
115
the color of Microalbuminuria results are compared with a chart on the reagent strip bottle after-
1 minute
116
microalbuminuria results read from-
0 - 10 mg/dL
117
immunodip reagent strips use ______ technique-
Immunochromographic technique
118
strips are packaged individually in-
Specially designed container for strip
119
Testing for Microalbuminuria place container in controlled amount of specimen for-
3 min
120
urine in Microalbuminuria tests enters container through a-
vent hole
121
Albumin binds to blue latex particles coated with-
antihuman albumin antibody
122
Bound and unbound particles migrate-
up strip
123
Unbound particles encounters area of immobilized albumin on strip & forms-
blue band
124
Bound particles continues migrating to an area of immobilized antibody and forms-
a second blue band
125
Color of the band is compared with-
manufacturers color chart
126
albumin reagent strip colors range from-
pale green to aqua blue
127
Visibly bloody urine elevates-
results
127
Abnormally colored urines may interfere with-
readings
128
The most frequent chemical analysis performed on urine-
glucose
129
Blood and urine glucose tests are included in-
all physical examinations
130
blood & urine glucose tests are often the focus of-
mass health screening programs
131
ureine & blood glucose tests are the major screening test for-
diabetes mellitus
132
ureine & blood glucose renal threshold is-
160 - 180 mg/dL
133
glycosuria-
higher blood sugar
134
ureine & blood glucose test recommendations-
fasting
135
urine & blood glucose test specimens are usually tested-
2 hours postprandial
136
gestational diabetes occurs when-
hormones secreted by the placenta block action of insulin
137
hormones secreted by the placenta block action of insulin causes- (3)
-High fetal glucose stresses baby’s pancreas
-Result is fat baby
-Mother prone to type 2 diabetes
138
Glucose oxidase reaction has a specific test for-
glucose
139
on glucose oxidase reagent strip test pad- (4)
-buffer
-glucose oxidase
-peroxide
-chromogen
140
Glucose oxidase, peroxide, chromogen, & buffer on the test pad produce-
Double sequential enzyme reaction
141
Glucose oxidase catalyzes a reaction between-
glucose and oxygen
142
Glucose oxidase catalyzes a reaction between glucose and oxygen producing- (2)
-gluconic acid
-peroxide
143
Peroxidase catalyzes the reaction between peroxide and chromogen to form-
an oxidized colored compound
144
Peroxidase forms an oxidized colored compound that is directly proportional to-
the concentration of glucose
145
chromogens used in Reagent Strip Glucose Oxidase Reactions- (2)
-Potassium iodide (green to brown) (Multistix)
-Tetramethylbenzidine (yellow to green) (Chemstrip)
146
chromagens reporting results- (2)
-Neg, trace, 1+, 2+, 3+, 4+
-100 mg/dL to 2 g/dL
147
False-positive glucose oxidase caused by-
only peroxide-oxidizing detergents from disinfectants used on lab instruments
148
False-negative glucose oxidase caused by- (3)
-Ascorbic acid and strong reducing agents
-High levels of ketones (unlikely)
-High specific gravity and low temperature
149
Greatest source of error is unpreserved specimens sitting at-
room temperature for extended periods, subjecting the glucose to bacterial degradation
150
Reduction of copper sulfate to cuprous oxide with-
alkali and heat
151
Clinitest tablets contain- (4)
-copper sulfate
-sodium carbonate
-sodium citrate
-sodium hydroxide
152
Sodium citrate + NaOH produce-
heat
153
CO2 is released from the sodium carbonate to prevent-
room air from interfering with the reduction reaction
154
Reducing substance + CuSO4 causes a color change- (4)
-negative blue (CuSO4)
-green
-yellow
-orange/red (Cu2O)
155
"Pass through” phenomenon may occur-
at high levels of glucose
156
when "pass through" occurs, rapid reaction happens & color passes through-
orange/red and returns to green-brown
157
repeat copper reduction clinitest with ____ procedure-
two-drop procedure
158
two drop procedure instructions- (4)
-10 drops water
-2 drops urine
-Values up to 5 g/L versus 2 g/L
-Separate chart must be used
159
clinitest is not a specific test for-
glucose
160
Sensitivity of clinitest to glucose-
200 mg/dL (lower) than strip
161
Clinitest does not provide a confirmatory test for-
glucose
162
clinitest has interference from reducing sugars- (8)
-Galactose
-lactose
-fructose
-maltose
-pentoses
-ascorbic acid
-certain drug metabolites
-antibiotics
163
Hygroscopic tablets deterioration due to moisture accumulation determined by-
strong blue color and excess fizzing
164
Galactose in the urine of a newborn signifies-
an “inborn error of metabolism”
165
galactose in urine of newborn- (2)
-Prevents breakdown of ingested galactose
-Results in failure to thrive and possible death
166
All states must screen for galactosemia as part of-
newborn screening process
167
early detection of galactose in urine of newborns method to control the condition-
Dietary restriction
168
ketones represents 3 intermediate products of-
fat metabolism
169
ketones fat metabolism- (3)
-Acetone: 2%
-Acetoacetic acid: 20%
-β-hydroxybutyrate: 78%
170
ketones appear in urine when-
body stores of fat must be metabolized to supply energy
171
clinical reasons for increased fat metabolism include-
inability to metabolize carbohydrate
172
primary causes for clinical significance of ketones in the urine- (3)
-Diabetes mellitus
-Vomiting (loss of carbohydrates)
-Starvation, malabsorption, dieting (↓ intake)
173
Ketonuria shows-
insulin deficiency
174
ketonuria indicates the need to monitor-
diabetes
175
Diabetic ketoacidosis-
increased accumulation of ketones in the blood
176
ketoacidosis leads to- (3)
-Electrolyte imbalance
-dehydration
-diabetic coma
177
Ketonuria is unrelated to-
diabetes
178
positive ketone tests produced because the patients illness shows- (5)
-Inadequate intake/absorption of carbohydrates
-Vomiting
-Weight loss
-Eating disorders
-Frequent strenuous exercise
179
Primary reagent strip for ketones-
sodium nitroprusside
(Nitroferricyanide)
180
sodium nitroprusside (Nitroferricyanide) Measure primarily-
acetoacetic acid
181
sodium nitroprusside (Nitroferricyanide) assumes the presence of-
β-hydroxybutyrate and acetone
182
Acetoacetic acid (alkaline) reacts with nitroprusside to produce-
purple color
183
reagent strip Report qualitatively- (5)
-Negative
-Trace
-Small (1+)
-Moderate (2+)
-Large (3+)
184
large dosages of levodopa & medications containing sulfhydryl groups may produce-
atypical color reactions
185
reactions with interfering substances may lead to false positive ketone results from-
improperly timed readings
186
Falsely decreased values in improperly preserved specimens breakdown-
acetoacetic acid by bacteria
187
Acetest tablet test used as confirmatory test for-
questionable results
188
acetest tablets primarily used for- (2)
-testing serum
-other bodily fluids
189
in tablet form, acetest provides- (4)
-sodium nitroprusside
-glycine
-disodium phosphate
-lactose (gives better color)
190
specimen should be absorbed in tablet within-
30 seconds
191
blood may be present in the urine in the form of- (2)
-hematuria
-hemoglobinuria
192
hematuria- (2)
-intact RBCs
-Cloudy red urine
193
hemoglobinuria- (2)
-product of RBC destruction
-Clear red urine
194
Any amount of blood greater than five cells per microliter of urine is considered-
clinically significant
195
Chemical tests for hemoglobin provide most accurate means for-
determining the presence of blood
196
microscopic examination can be used to differentiate between-
hematuria and hemoglobinuria
197
hematuria is most closely related to-
damage of renal system
198
major causes of hematuria include- (7)
-Renal calculi
-Glomerular disease
-Tumors
-Trauma
-Pyelonephritis
-Exposure to toxic chemicals
-Anticoagulant therapy
199
when the amount of free hemoglobin present exceeds the hepgaotglobin content is caused by- (6)
-Hemolytic anemias
-Transfusion reactions
-Severe burns
-Brown recluse spider bites
-Infections
-Strenuous exercise
200
Hemoglobinuria may result from-
the lysis of red blood cells in dilute, alkaline urine
201
Hemosiderin appears as-
yellow brown granules in sediment
202
Myoglobinuria is a heme-containing protein in muscle tissue produces-
clear, red/brown urine
203
Rhabdomyolysis also called-
muscle destruction
204
Rhabdomyolysis examples- (8)
-Muscular trauma/crush syndromes
-Prolonged coma
-Convulsions
-Muscle-wasting diseases
-Alcoholism
-Heroin abuse
-Extensive exertion
-Cholesterol-lowering statin medications
205
Principle pseudoperoxidase is the activity of-
hemoglobin
206
pseudoperoxidase catalyze a reaction between the-
heme component
207
reactions between the heme component of- (3)
-Hemoglobin and myoglobin
-Chromogen tetramethylbenzidine
-Produce an oxidized chromogen (Green-blue color)
208
2 reagent strip color charts are provided that correspond to-
the reactions that occur
209
free hemoglobin shows-
uniform color
210
intact RBCs show-
speckled pattern on the pad
211
used for reporting intact RBCs- (4)
-trace
-small (1+)
-moderate (2+)
-large (3+)
212
intact RBCs sensitivity-
5 RBCs/μL
213
false positive for blood in the urine- (4)
-menstrual contamination
-strong oxidizing agents
-vegetable peroxidase
-bacterial peroxidases
214
false negative for blood in the urine- (6)
-Ascorbic acid >25 mg/dL
-High SG/crenated cells
-Formalin
-Captopril
-High concentrations of nitrite
-Unmixed specimens
215
Urine bilirubin is an early indicator of-
liver disease
216
bilirubin is a normal degradation product of-
hemoglobin
217
RBCs destroyed by liver and spleen following-
120-day life span
218
body recycles- (2)
-iron
-protein
219
protoporphyrin is broken down into-
bilirubin
220
bilirubin is bound to-
albumin
221
kidneys cannot excrete-
bilirubin
222
unconjugated bilirubin-
water insoluble: indirect
223
Conjugated bilirubin-
water soluble: direct
224
in the liver, bilirubin is conjugated with-
glucuronic acid
225
when bilirubin is conjugated with glucuronic acid, it forms
conjugated bilirubin
226
conjugated bilirubin passes from-
liver to intestines
227
intestinal bacteria reduces bilirubin to- (3)
-urobilinogen
-stercobilinogen
-urobilin
228
bilirubin is excreted in-
feces
229
Conjugated bilirubin appears in urine with- (2)
-bile duct obstruction
-liver disease or damage
230
Bilirubin backs up into circulation and is excreted in-
urine, no Urobilinogen is formed
231
Hepatitis, cirrhosis-
Conjugated bilirubin leaks back into circulation from damaged liver; some bilirubin passes to intestine
232
Detection of bilirubin can also be used in determining the cause of-
clinical jaundice
233
bilirubin reagent strip principle is-
diazo reaction
234
bilirubin reactions reported as- (4)
-neg
-small (1+)
-moderate (2+)
-large (3+)
235
diazo reagent strip colors may be difficult to interpret because-
they're easily influenced by other pigments present in the urine
236
atypical colors in diazo reagent strips can be problematic for-
automated readers
237
false positive in bilirubin tests caused by- (3)
-Urine pigments
-Pyridium (phenazopyridine)
-Lodine (NSAID)
238
false negative in bilirubin tests caused by- (3)
-Old specimens (biliverdin does not react)
-Ascorbic acid >25 mg/dL
-Nitrite
239
nitrite may cause false negatives in bilirubin tests because-
substances combine with diazonium salt and block bilirubin reaction
240
Confirmatory test for bilirubin-
ictotest
241
ictotest tablets contain- (4)
-p-nitrobenzene-diazonium-p-toluenesulfonate
-SSA
-sodium carbonate
-boric acid
242
ictotest mats keeps-
bilirubin on surface for reaction
243
ictotest positive reaction (color)-
blue - purple color
244
interfering substances in ictotest-
are washed into the mat, and only bilirubin remains on the surface
245
Bilirubin in intestines is converted to-
-urobilinogen
-stercobilinogen
246
urobilinogen is reabsorbed into-
circulation
247
stercobilinogen cannot be reabsorbed, but is oxidized to-
stercobilin
248
Pigments responsible for the characteristic brown color of feces- (2)
-stercobilin
-urobilin
249
measurement of urobilinogen filtered by the kidneys & found in the urine-
less than 1 mg/dL (less than 1 EU/dL)
250
increased urine urobilinogen is the early detection of- (2)
-liver disease
-hemolytic disorders
251
measurement of increased urine urobilinogen-
greater than 1 mg/dL (EU/dL)
252
disorders associated with increased urin Urobilinogen- (4)
-Liver disorders
-hepatitis
-cirrhosis
-carcinoma
253
hemolytic disorders in increased urine urobilinogen-
Excess bilirubin being converted to urobilinogen and ↑ urobilinogen recirculated to liver
254
Negative bilirubin and strong positive urobilinogen are seen in-
hemolytic disorders
255
when urobilinogen tests are performed ____% of the non-hospitalized population show elevated results-
1%
256
when urobilinogen tests are performed ____% of the hospitalized population show elevated results-
9%
257
elevated urobilinogen results are frequently caused by-
constipation
258
No urobilinogen is seen in the urine with-
bile duct obstruction (strip will give normal results
259
urobilinogen reagent strips cannot report-
a negative reading
260
urobilinogen reagent strip reactions differ between- (2)
-Multistix
-Chemstrip
261
multistix uses a modification of Ehrlich’s reaction where urobilinogen reacts with-
p-dimethylaminobenzaldehyde (Ehrlich reagent)
262
multistix results are reported in-
Ehrlich units (EU) 1 EU = 1 mg/dL
263
multistix normal readings- (3)
-0.2 - 1
-abnormal
-2,4,8
264
multistix color reading-
light to dark pink
265
chemstrip uses _____ reaction-
diazo (azo-coupling) reaction
266
chemstrip diazo (azo-coupling) reaction using-
4-Methoxybenzene-diazonium-tetrafluoroborate (more specific than Ehrlich reaction)
267
chemstrip results reported in-
mg/dL
268
chemstrip color reaction-
white - pink
269
Ehrlich reactive compounds- (7)
-porphobilinogen
-indican
-p-aminosalicylic acid
-sulfonamides
-methyldopa
-procaine
-chlorpromazine
270
ehrlich testing should be at-
room temp
271
urobilinogen is highest- (2)
-after meals (increased bile salts)
-old specimens & formalin preservation decrease results
272
Chemstrip false-negative with-
high nitrite interferes with diazo reaction
273
nitrite tests-
Rapid screening test for the presence of urinary tract infection (UTI)
274
nitrite tests valuable for detecting-
cystitis (initial bladder infection)
275
pyelonephritis (tubules) caused by-
untreated cystitis
276
nitrite test also used for- (2)
-Evaluation of antibiotic therapy
-Monitoring of patients at high risk for urinary tract infection
277
many labs use nitrite test in combination with LE test to-
Screen urine culture specimens
278
UTIs most commonly caused by gram-negative organisms- (4)
-E. Coli
-Proteus species
-Enterobacter species
-Klebsiella species
279
chem basis of nitrite test is the ability of bacteria to-
reduce nitrate (normal constituent) to nitrite (abnormal)
280
greiss reaction happens when nitrite reacts with aromatic amine to form-
diazonium salt that then reacts with tetrahydrobenzoquinoline to form a pink azodye
281
nitrite tests correspond with a quantitative bacterial culture criterion of-
100,000 organisms/mL
282
nitrite test results reported as- (2)
-negative
-positive
283
causes false negative in nitrite tests- (7)
-Non-reductase-containing bacteria
-Insufficient contact time between bacteria and urinary nitrate
-Lack of urinary nitrate
-Large quantities of bacteria converting nitrite to nitrogen
-Presence of antibiotics
-High concentrations of ascorbic acid
-High specific gravity
284
negative nitrite test results in the presence of even vaguely suspicious clinical symptoms should always be - (2)
-repeated
-followed by a urine culture
285
leukocyte esterase tests offers-
more standardized means for the detection of leukocytes
286
purpose of LE tests-
detect leukocytes so as not to rely on microscopic
287
advantage of LE tests-
detects presence of lysed leukocytes
288
LE tests aren't considered-
quantitative tests
289
if LE tests are positive, perform-
microscopic
290
LE test normal values vary from-
0 - 2 to 0 - 5 per high-power field (hpf)
291
increased WBCs in LE tests indicate-
UTI
292
Neutrophils are most frequently associated with-
bacterial infections
293
LE tests also seen with- (4)
-Trichomonas
-Chlamydia
-yeast
-interstitial nephritis
294
LE catalyzes hydrolysis of acid esterase on pad to- (2)
-aromatic compound
-acid
295
aromatic compound reacts with diazonium salt on pad for-
purple color
296
LE reaction requires-
the longest time of all the reagent strip reactions (2 min)
297
LE results reported as- (4)
-Trace
-Small: 1+
-Moderate: 2+
-Large: 3+
298
LE trace readings may not be significant and should be repeated on-
a fresh specimen
299
LE false positive caused by- (3)
-Strong oxidizing agents
-Formalin
-Highly pigmented urine, nitrofurantoin
300
LE false negative caused by- (4)
-High concentrations of protein, glucose, oxalic acid, ascorbic acid
-Crenation from high specific gravity
-Inaccurate timing: must have 2 min
-Presence of the antibiotics; gentamicin, cephalosporins, tetracyclines
