AUBF [LEC] - Chemical Examination of Urine Flashcards
1
Q
Is a urine dipstick qualitative?
A
False, it is semi-quantitative.
2
Q
What are chemically impregnated absorbent pads attached to?
A
Reagent strip.
3
Q
What are the testing considerations for a reagent strip?
A
- Perform within 1 hour after collection. 2. Allow refrigerated specimen to return to room temperature. 3. Compare color after appropriate time period.
4
Q
If the urine has many sediments, how many inversions should be done?
A
3-5 times.
5
Q
Do automated reagent strip instruments standardize color interpretation?
A
True.
6
Q
What type of containers should be used for handling urine samples?
A
Opaque containers with desiccant.
7
Q
What is the recommended storage temperature for urine samples?
A
Room temperature below 30°C.
8
Q
Should positive and negative controls be used every 24 hours?
A
True.
9
Q
Is distilled water used as a negative control?
A
False, it is not used.
10
Q
What does pH measure in urine?
A
Degree of acidity and alkalinity.
11
Q
What is the pH level of first morning urine?
A
Slightly acidic, pH 5 - 6.
12
Q
What is the pH of normal urine specimens?
A
4.5 - 8.0.
13
Q
Are normal values assigned for pH?
A
False.
14
Q
Which organs regulate acid-base balance in the body?
A
Lung and kidney.
15
Q
What does pH detect?
A
Systemic acid-base disorders (metabolic or respiratory).
16
Q
What is the pH level in respiratory/metabolic acidosis that is not related to renal function?
A
Acidic.
17
Q
What is the pH level when respiratory/metabolic acidosis is present?
A
Alkaline.
18
Q
Can pH be used to promote inhibition of stone formation?
A
True.
19
Q
Can pH be used to treat UTI?
A
True.
20
Q
What type of pH is found in specimens preserved for extended periods due to urea splitting bacteria?
A
Alkaline.
21
Q
Do urea splitting bacteria multiply readily in acidic urine?
A
False, they do not.
22
Q
What type of diet leads to acidic urine?
A
High protein diet.
23
Q
What type of urine is associated with vegetarians?
A
Alkaline.
24
Q
What pH level is associated with improperly preserved specimens?
A
Above 8.5 or 9.
25
What is the effect of cranberry juice on urine pH?
It makes urine acidic.
26
What is used as a home remedy for minor bladder infections?
Cranberry juice.
27
What is the principle of the pH test?
Double indicator system.
28
What reagents are used in the pH test?
Methyl red and bromthymol blue.
29
What color change does methyl red indicate in pH 4-6?
Red to yellow.
30
What color change does bromthymol blue indicate in pH 6-9?
Yellow to blue.
31
What color progression occurs in pH 5-9?
Colors progress from orange at pH 5 to deep blue at pH 9.
32
What are the increments of pH?
0.5 or 1 unit increments.
33
Is there any known substance that interferes with urinary pH?
True.
34
What is the most indicative analyte of renal disease?
Protein.
35
Can tamm horsfall and bence jones proteins be detected in protein reagent strip?
False.
36
What analyte is often associated with early renal disease?
Protein.
37
What is the normal amount of protein in urine?
Less than 10 mg/dL or 100 mg/24 hrs.
38
What is the major serum protein found in urine?
Albumin.
39
Is albumin filtered and reabsorbed in high amounts?
False, protein is low.
40
What protein is produced by tubules from prostatic fluid and vaginal secretions?
Tamm horsfall protein.
41
In a creatinine clearance test, if the patient is positive, what is malfunctioning?
Glomerulus.
42
What is an early biomarker for diabetes mellitus and cardiovascular diseases?
Microalbuminuria.
43
Why is protein present in low concentration in urine?
It is protected by a shield of negativity and thus reabsorbed.
44
Does protein always signify renal disease?
True, additional testing is required.
45
What are the clinical proteinuria levels?
Greater than 30 mg/dL (300 mg/L) in 24 hours.
46
What is prerenal proteinuria?
Conditions affecting plasma prior to reaching the kidney, not indicative of renal disease.
47
What causes prerenal proteinuria?
Hemoglobin, low MW plasma proteins, myoglobin, APRs in inflammation, and infection.
48
What protein is associated with patients with multiple myeloma?
Bence jones protein.
49
What is the turbidity of Bence jones proteins in prerenal proteinuria at 40-60°C?
Turbid; clear at 100°C.
50
What does renal proteinuria indicate?
True renal disease (glomerular or tubular damage).
51
What is impaired in glomerular renal proteinuria?
Selective filtration.
52
What happens to serum proteins and RBCs in glomerular renal proteinuria?
They pass through and are excreted in urine.
53
What condition is associated with preeclampsia?
Glomerular renal proteinuria.
54
What is preeclampsia?
Part of pregnancy where blood pressure increases to the point that albumin is released in urine.
55
What does tubular renal proteinuria affect?
Reabsorption of normally filtered albumin.
56
What can cause tubular renal proteinuria?
Toxic substances exposure.
57
What are some causes of tubular renal proteinuria?
Heavy metals, viral infections, and Fanconi syndrome.
58
What is Fanconi syndrome?
Condition where renal tubules cannot reabsorb solutes.
59
What affects glomerular pressure, releasing protein in urine?
Orthostatic/postural/cadet proteinuria.
60
What is transient proteinuria?
When proteinuria is temporary and returns to normal after strenuous exercise.
61
What is microalbuminuria associated with?
Development of diabetic neuropathy leading to reduced glomerular filtration and eventual renal failure.
62
What does microalbuminuria indicate?
Onset of renal complications; associated with increased risk of CVD.
63
What is the normal amount of albumin in urine in random specimens?
10 mg/dL.
64
What is clinically significant proteinuria in random specimens?
30 mg/dL.
65
What is the principle of the micral test for microalbumin?
Enzyme immunoassay.
66
What is the principle of immunodip for microalbumin?
Immunochromatographics.
67
What test uses a gold-labeled antibody for microalbumin?
Micral test.
68
What test uses antibody-coated blue latex particles for microalbumin?
Immunodip.
69
What is the tablet test for microalbumin?
Clinitest.
70
What is an interference in clinitest?
Bloody urine.
71
What is post renal proteinuria?
Proteinuria added to urine as it passes through the lower urinary tract.
72
What is the principle of protein testing?
Protein errors of indicators.
73
What reagents are used in the protein test?
Tetrabromphenol blue, tetrachlorophenol, tetrabromosulfonphthalein + acid buffer.
74
What does the acid buffer in protein testing maintain the pH at?
3.0.
75
Is there a pH indicator in the protein test?
True.
76
What is the most frequent chemical analysis on urine?
Glucose.
77
Is glucose normally found in urine?
False, it is not found even in minute amounts.
78
What is glucose used for?
Detection and monitoring of diabetes mellitus.
79
What is the recommended specimen for glucose testing?
Fasting urine.
80
Where is almost all glucose filtered by the glomerulus reabsorbed?
Proximal convoluted tubule (PCT).
81
What type of transport is glucose reabsorption?
Active transport.
82
What specimen is used for diabetes monitoring?
2 hour postprandial.
83
What specimen is used for gestational diabetes?
Oral Glucose Tolerance Test (OGTT).
84
Can insulin cross the placenta?
False, glucose can cross but insulin cannot.
85
What is the principle of glucose testing?
Double sequential enzyme reaction.
86
What enzymes are involved in glucose testing?
Glucose oxidase and peroxidase.
87
What is the tablet test for glucose?
Clinitest - for carbohydrates.
88
What is the principle of clinitest?
Benedict's test; positive for reducing sugars, negative for non-reducing sugars (sucrose).
89
What do ketones represent?
Intermediate products of fat metabolism.
90
What are the three intermediate products of fat metabolism?
Acetone, acetoacetic acid, and hydroxybutyric acid.
91
What metabolic process produces ketones?
Gluconeogenesis.
92
What are acetone and beta hydroxybutyric acid produced from?
Acetoacetic acid.
93
What are the three intermediate products of fat metabolism?
Ketones
94
What are the three intermediate products of fat metabolism?
Acetone, acetoacetic acid, hydroxybutyric acid
95
What metabolic process produces ketones?
Gluconeogenesis
96
What is produced from acetoacetic acid?
Acetone and beta hydroxybutyric acid
97
What are the percentages of the three intermediate products of fat metabolism?
B-hydroxybutyric acid - 78%, acetoacetic acid - 20%, acetone - 2%
98
What is another name for acetoacetic acid?
Diacetic acid
99
What is the main chemical structure detected for ketones?
Acetoacetic acid
100
Is the reaction from acetoacetic acid to acetone reversible?
False
101
What is most valuable in the management and monitoring of type 1 diabetes mellitus?
Ketones
102
What indicates a deficiency in insulin?
Ketonuria
103
What does increased accumulation of ketones in blood lead to?
Electrolyte imbalance, dehydration, acidosis, and eventual diabetic coma
104
What is the principle of ketones?
Sodium nitroprusside (nitroferricyanide)
105
What is added in the regular reaction of ketones to detect acetone?
Glycine
106
What enzyme is involved in ketones?
Aldolase
107
What is the end color of ketone detection?
Purple color
108
How many RBCs per microliter of urine is considered clinically significant?
>5 RBC
109
What provides the most accurate means of determining the presence of blood?
Hemoglobin testing
110
What can be used to differentiate once blood has been detected?
Microscopic examination
111
What is the term for intact RBCs in urine?
Hematuria
112
What is the term for hemoglobin in urine?
Hemoglobinuria
113
What is the term for blood from muscles in urine?
Myoglobinuria
114
What condition is characterized by a speckled pattern?
Hematuria
115
What condition is indicated by a homogeneous blood reagent strip?
Myoglobinuria or hemoglobinuria
116
What is most closely related to disorders of renal or genitourinary origin?
Hematuria
117
What does cloudy red urine indicate?
Hematuria
118
What does clear red specimen indicate?
Hemoglobinuria
119
What may result from the lysis of RBCs produced in the urinary tract?
Hemoglobinuria
120
Are RBCs seen in cases of intravascular hemolysis?
True
121
What condition prevents the glomerular filtration of hemoglobin?
Hemoglobinuria
122
What conditions can lead to hemoglobinuria?
Hemolytic anemias, transfusion reactions, severe burns, spider bites, infections & strenuous exercise
123
Is hemoglobin unavailable for glomerular filtration?
False, it is available
124
What test is used to differentiate hemoglobinuria?
Blonthein test
125
How many grams of ammonium sulfate are used in the Blonthein test?
2.8 grams
126
What does clear red urine + ammonium sulfate = yellow indicate?
Hemoglobinuria
127
What does clear red urine + ammonium sulfate = no change indicate?
Myoglobinuria
128
What is the heme-containing protein found in muscle tissue?
Myoglobin
129
What does myoglobin produce in urine?
Clear red-brown urine
130
In what conditions is myoglobin associated?
Muscle destruction (rhabdomyolysis)
131
What is a side effect of cholesterol-lowering statin medications?
Myoglobin
132
Is myoglobin toxic to renal tubules?
True, its heme portion is toxic
133
Can high concentrations of myoglobin in renal tubules cause acute renal failure?
True
134
In what conditions is myoglobin seen?
Trauma, crush syndromes, prolonged coma, convulsions, muscle wasting disease, alcoholism, heroin abuse, extensive exertions
135
In hemoglobinuria, is the plasma clear since hemoglobin is dangerous to kidneys?
False, myoglobinuria; the heme portion is toxic
136
What is the principle of blood detection?
Peroxidase activity of hemoglobin
137
What is the substrate used in blood detection?
Tetramethylbenzidine
138
What is the end color of blood detection?
Green-blue color
139
What protein/enzyme is used in blood detection?
Hemoglobin/peroxidase
140
What color range does blood detection show?
Uniform color ranging from yellow (negative) through green to strong positive green-blue
141
Can reagent pads detect as low as 5 RBC per microliter?
True
142
Are ketones seen normally in urine?
True, in minute amounts
143
What is a byproduct of the breakdown of hemoglobin?
Bilirubin
144
Does urine contain minute amounts of bilirubin?
False
145
What type of bilirubin is seen in urine?
B1
146
What appears in urine in obstruction of bile ducts?
Bilirubin
147
What appears in urine when there is liver damage causing leakage?
B1
148
What are two common examples of bilirubinemia?
Hepatitis and cirrhosis
149
What is an early indication of liver disease?
Urinary bilirubin
150
Is serum bilirubin present in unconjugated form and cannot be excreted by kidneys?
True
151
Is urobilinogen normally found in minute concentrations in urine?
True
152
What is the principle of bilirubin detection?
Diazoreaction
153
What can cause false positives in bilirubin detection?
Urine pigments, intake of phenazopyridine, indican, metabolites
154
What can cause bilirubin detection issues?
Unfresh specimen, light, hydrolysis of bilirubin diglucuronide, high ascorbic acid
155
Does biliverdin also react with the diazo test?
False
156
What are the normal concentrations of urobilinogen found in urine?
<1 mg/dl or 1 ehrlich unit
157
What pigment is responsible for the brown color of feces?
Urobilin
158
What appears in urine because it circulates in the blood en route to the liver?
Urobilinogen
159
Is urobilinogen increased in hemolytic disorders?
True
160
What does low concentration of urobilinogen indicate?
Liver disease
161
What is the bilirubin and urobilinogen result in biliary obstruction?
Bilirubin (+), urobilinogen (-)
162
What is the bilirubin and urobilinogen result in parasites?
Urobilinogen increase
163
What is the bilirubin and urobilinogen result in liver diseases like hepatitis or cirrhosis?
Both trace
164
What is the principle of urobilinogen detection?
Ehrlich's aldehyde reaction and azocoupling (diazo) reaction
165
What is Ehrlich's reagent?
p-dimethylaminobenzaldehyde
166
What test uses a modification of Ehrlich reactions from light to dark pink?
Multistix
167
What test is more specific and incorporates azo coupling diazo reaction?
Chemstrip
168
What is the diazonium salt of Chemstrip for urobilinogen?
4-methoxybenzene-diazonium-tetrafluoroborate
169
What is the end color of Chemstrip for urobilinogen?
Red azodye
170
What test differentiates urobilinogen, porfobilirogen, and other Ehrlich reactive substances?
Watson Schwartz differentiation test
171
What does Watson Schwartz use?
Chloroform and butanol
172
What are the results of Watson Schwartz test?
Urobilinogen = miscible in both, porfobilirogen = immiscible in both, ehrlich reactive substance = only miscible with one
173
What is the ability of bacteria to reduce nitrate to nitrite?
Nitrite
174
What is a rapid screening test for the presence of UTI?
Nitrite
175
What is the primary test for diagnosing and monitoring bacterial infection?
Nitrite
176
What is used for bladder infection?
Nitrite
177
What is the lower UTI involving the urinary bladder?
Bladder infection (cystitis)
178
What is the upper UTI?
Pyelonephritis
179
What is the inflammatory process of the kidney and adjacent renal pelvis?
Pyelonephritis
180
What are the gram-negative bacteria causing UTI?
E. coli, Proteus, Enterobacter, Klebsiella
181
How much more common is UTI in women compared to men?
8 times, due to shorter urethra
182
In which patients does UTI have a higher incidence?
Catheterized patients
183
What is the principle of nitrite detection?
Greiss reaction
184
What does nitrite come from?
Green leafy vegetables
185
What happens if there is no source of nitrate?
The reagent strip would be negative
186
What is required for enough contact time to convert nitrate to nitrite?
4-hour urine sample
187
What is the substrate in nitrite detection?
Tetrahydrobenzoquinolone
188
What is the end product of nitrite detection?
Pink azodye
189
Can nitrite measure the degree of bacteriuria?
False, it cannot
190
Is any shade of pink clinically significant for bacteria in nitrite detection?
True
191
What suggests bacteriuria in the presence of WBCs?
Leukocyte esterase
192
What offers a more standardized means for detection of WBCs?
Leukocyte esterase
193
Is leukocyte esterase designed to measure leukocyte concentration?
True
194
What does leukocyte esterase detect?
Presence of leukocytes that have been lysed
195
What does leukocyte esterase indicate in urine?
It suggests the presence of WBCs and strongly indicates bacteriuria.
196
What does AUBF stand for?
AUBF stands for Automated Urine Biochemical Analysis.
197
True or False: Leukocyte esterase is designed to measure leukocyte concentration.
False
198
What does leukocyte esterase detect?
It detects the presence of lysed leukocytes, particularly in dilute alkaline specimens.
199
What are the normal values for WBC in urine?
0-2.5/hpf
200
What are the three positive results for leukocyte esterase?
1. Histiocytes
2. Neutrophils (granulocytic WBC eosino, baso)
3. Trichomonas vaginalis
201
True or False: Lymphocytes, RBCs, bacteria, and renal tissue contain leukocyte esterase.
False
202
What is the reaction time required for leukocyte esterase?
It requires the longest time of all the reagent strip reactions (2 minutes).
203
What is the principle of leukocyte esterase?
Leukocyte esterase principle
204
What is the end product of leukocyte esterase?
Purple azodye
205
What can cause a false positive in leukocyte esterase testing?
Strong oxidizing agents and formalin.
206
What can cause a false negative in leukocyte esterase testing?
Protein, glucose, oxalic acid, ascorbic acid.
207
True or False: Antibiotics such as gentamicin, cephalexin, cephalothin, and tetracycline can decrease the sensitivity of the leukocyte esterase reaction.
True
208
What does specific gravity reflect?
It reflects the kidney's ability to concentrate.
209
What does specific gravity monitor?
It monitors patient hydration and dehydration, loss of renal tubular concentrating ability, and diabetes insipidus.
210
What is the principle of specific gravity?
pKa change
211
What is the 11th parameter in urine chemical examination?
Ascorbic acid
212
What is the principle and reagent of ascorbic acid testing?
Tillman's reaction; Tillman's reagent
213
What is Tillman's reagent?
2,6-dichloroindophenol sodium
214
What color change indicates the presence of ascorbic acid?
Blue to green
215
Ascorbic acid interferes with which tests?
Blood, glucose, nitrite, leukocyte.
216
What is the normal value for urine pH?
5.5 to 8.0
217
What is the normal value for urobilinogen?
0.2 to 1.0 ehrlich units
218
What can cause inaccurate results in urine testing?
Failure to observe color changes at appropriate time intervals.
219
What should be ensured while observing color changes in urine testing?
Good lighting.
220
Why should reagent strips be tested with positive controls?
To ensure proper reactivity.
221
What is necessary for the preservation of urine chemical samples?
Proper collection and storage.
222
What happens if cold specimens are tested?
It results in a slowing down of reactions; test specimens when fresh or bring them to room temperature before testing.
223
What can inadequate mixing of specimens lead to?
False reduced or negative reactions to blood and leukocyte tests.
224
What can over-dipping of reagent strips result in?
Leaching of reagents out of pads; briefly, but completely dip the reagent strip into the urine.
