comp 3 Flashcards

1
Q

Which statement regarding renal function is true?
A. Glomeruli are far more permeable to H2O and
salt than other capillaries
B. The collecting tubule reabsorbs sodium and
secretes potassium in response to antidiuretic
hormone (ADH)
C. The collecting tubule is permeable to H2O only
in the presence of aldosterone
D. The thick ascending limb is highly permeable to
H2O and urea

A

a

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2
Q

Which statement regarding normal salt and H2O handling by the nephron is correct?
A. The ascending limb of the tubule is highly
permeable to salt but not H2O
B. The stimulus for ADH release is low arterial
pressure in the afferent arteriole
C. The descending limb of the tubule is impermeable
to urea but highly permeable to salt
D. Renin is released in response to high plasma
osmolality

A

a

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3
Q

Which statement concerning renal tubular function is true?
A. In salt deprivation, the kidneys will conserve
sodium at the expense of potassium
B. Potassium is not excreted when serum concentration is below 3.5 mmol/L
C. No substance can be excreted into urine at a rate that exceeds the glomerular filtration rate
D. When tubular function is lost, the specific gravity of urine will be below 1.005

A

a

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4
Q

Which of the following is inappropriate when collecting urine for routine bacteriologic culture?
A. The container must be sterile
B. The midstream void technique must be used
C. The collected sample must be plated within
2 hours unless refrigerated
D. The sample may be held at 2°C–8°C for up
to 48 hours prior to plating

A

d

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5
Q

Which statement about sample collection for routine urinalysis is true?
A. Preservative tablets should be used for collecting
random urine specimens
B. Containers may be washed and reused if rinsed
in deionized H2O
C. Samples may be stored at room temperature for
up to 2 hours
D. First morning voided samples are not acceptable
when renal disease is suspected

A

c

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6
Q

Which urine color is correlated correctly with the pigment-producing substance?
A. Smoky red urine with homogentisic acid
B. Dark amber urine with myoglobin
C. Deep yellow urine and yellow foam with bilirubin
D. Red-brown urine with biliverdin

A

c

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7
Q

Which of the following substances will cause urine
to produce red fluorescence when examined with
an ultraviolet lamp (360 nm)?
A. Myoglobin
B. Porphobilinogen (PBG)
C. Urobilin
D. Coproporphyrin

A

d

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8
Q

Which of the following conditions is associated
with normal urine color but produces red
fluorescence when urine is examined with an
ultraviolet (Wood’s) lamp?
A. Acute intermittent porphyria
B. Lead poisoning
C. Erythropoietic porphyria
D. Porphyria cutanea tarda

A

b

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9
Q

Which statement regarding porphyria is accurate?
A. Porphyria is exclusively inherited
B. All types cause an increase in urinary porphyrins
C. All types are associated with anemia
D. Serum, urine, and fecal tests may be needed for diagnosis

A

d

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10
Q

Which is the most common form of porphyria?
A. Erythropoietic porphyria
B. Acute intermittent porphyria
C. Variegate porphyria
D. Porphyria cutanea tarda

A

d

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11
Q

Which of the following methods is the least
sensitive and specific for measuring PBG in urine?
A. Watson–Schwartz test
B. LC–MS
C. Ion exchange chromatography–Ehrlich’s reaction
D. Isotope dilution–MS

A

a

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12
Q

A brown or black pigment in urine can be
caused by:
A. Gantrisin (Pyridium)
B. Phenolsulfonphthalein
C. Rifampin
D. Melanin

A

d

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13
Q

Urine that is dark red or port wine in color may be
caused by:
A. Lead poisoning
B. Porphyria cutanea tarda
C. Alkaptonuria
D. Hemolytic anemia

A

b

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14
Q

Which of the following tests is affected least by
standing or improperly stored urine?
A. Glucose
B. Protein
C. pH
D. Bilirubin

A

b

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15
Q

Which type of urine sample is needed for a
D-xylose absorption test on an adult patient?
A. 24-hour urine sample collected with 20 mL
of 6 N HCl
B. 2-hour timed postprandial urine preserved with
boric acid
C. 5-hour timed urine kept under refrigeration
D. Random urine preserved with formalin

A

c

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16
Q

Which of the following is inappropriate
when collecting a 24-hour urine sample for
catecholamines?
A. Urine in the bladder is voided and discarded at
the start of the test
B. At 24 hours, any urine in the bladder is voided
and added to the collection
C. All urine should be collected in a single container
that is kept refrigerated
D. Ten mL of 1N sodium hydroxide should be
added to the container before collection

A

d

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17
Q

Urine production of less than 400 mL/day is:
A. Consistent with normal renal function and
H2O balance
B. Termed isosthenuria
C. Defined as oliguria
D. Associated with diabetes mellitus

A

c

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18
Q

Which of the following contributes to SG, but
not to osmolality?
A. Protein
B. Salt
C. Urea
D. Glucose

A

a

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19
Q

Urine with an SG consistently between 1.002
and 1.003 indicates:
A. Acute glomerulonephritis
B. Renal tubular failure
C. Diabetes insipidus
D. Addison’s disease

A

c

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20
Q

In which of the following conditions is the urine
SG likely to be below 1.025?
A. Diabetes mellitus
B. Drug overdose
C. Chronic renal failure
D. Prerenal failure

A

c

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21
Q

Which statement regarding methods for
measuring SG is true?
A. To correct a urinometer, subtract 0.001 per each
3°C below 15.5°C
B. Colorimetric SG tests are falsely elevated when a
large quantity of glucose is present
C. Colorimetric SG readings are falsely elevated
when pH is alkaline
D. Refractometry should be performed before the urine is centrifuged

A

a

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22
Q

What is the principle of the colorimetric reagent
strip determination of SG in urine?
A. Ionic strength alters the pKa of a polyelectrolyte
B. Sodium and other cations are chelated by a
ligand that changes color
C. Anions displace a pH indicator from a mordant,
making it water soluble
D. Ionized solutes catalyze oxidation of an azo dye

A

a

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23
Q

Which statement regarding urine pH is true?
A. High-protein diets promote an alkaline urine pH
B. pH tends to decrease as urine is stored
C. Contamination should be suspected if urine pH
is less than 4.5
D. Bacteriuria is most often associated with a low urine pH

A

c

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24
Q

In renal tubular acidosis, the pH of urine is:
A. Consistently acid
B. Consistently alkaline
C. Neutral
D. Variable, depending upon diet

A

b

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25
Q

The normal daily urine output for an adult is
approximately:
A. 0.2–0.5 L
B. 0.6–1.6 L
C. 2.7–3.0 L
D. 3.2–3.5 L

A

b

26
Q

The SG of the filtrate in Bowman’s space is
approximately:
A. 1.000–1.002
B. 1.004–1.006
C. 1.008–1.010
D. 1.012–1.014

A

c

27
Q

A patient with partially compensated respiratory
alkalosis would have a urine pH of:
A. 4.5–5.5
B. 5.5–6.5
C. 6.5–7.5
D. 7.5–8.5

A

d

28
Q

Which of the following is most likely to cause a
false-positive dry reagent strip test for urinary
protein?
A. Urine of high SG
B. Highly buffered alkaline urine
C. Bence–Jones protein
D. Salicylates

A

b

29
Q

When testing for urinary protein with
sulfosalicylic acid (SSA), which condition
may produce a false-positive result?
A. Highly buffered alkaline urine
B. The presence of x-ray contrast media
C. Increased urinary SG
D. The presence of red blood cells (RBCs)

A

b

30
Q

A discrepancy between the urine SG determined
by measuring refractive index and urine osmolality
would be most likely to occur:
A. After catheterization of the urinary tract
B. In diabetes mellitus
C. After an intravenous pyelogram (IVP)
D. In uremia

A

c

31
Q

Which of the following is likely to result in a
false-negative dry reagent strip test for
proteinuria?
A. Penicillin
B. Aspirin
C. Amorphous phosphates
D. Bence–Jones protein

A

a

32
Q

Daily loss of protein in urine normally does not
exceed:
A. 30 mg
B. 50 mg
C. 100 mg
D. 150 mg

A

d

33
Q

Which of the following is least likely to cause a
false-positive result with turbidimetric protein
tests?
A. Tolbutamide
B. X-ray contrast media
C. Penicillin or sulfa antibiotics
D. Ascorbic acid

A

d

34
Q

Which statement best describes the clinical utility of tests for microalbuminuria?
A. Testing may detect early renal involvement in diabetes mellitus
B. Microalbuminuria refers to a specific subfraction of albumin found only in persons with diabetic
nephropathy
C. A positive test result indicates the presence of orthostatic albuminuria
D. Testing should be part of the routine urinalysis

A

a

35
Q

Dry reagent strip tests for microalbuminuria that compare albumin to creatinine determine the creatinine concentration based upon which
principle?
A. Formation of a Cu+2-creatinine complex
B. Enzymatic assay using sarcosine oxidase and
peroxidase
C. Reaction of creatinine with alkaline sodium
picrate
D. Change in pH as creatinine is converted to
creatine

A

a

36
Q

Which of the following conditions is least likely
to be detected by dry reagent strip tests for
proteinuria?
A. Orthostatic albuminuria
B. Chronic renal failure
C. Pyelonephritis
D. Renal tubular proteinuria

A

d

37
Q

The normal renal threshold for glucose is:
A. 70–85 mg/dL
B. 100–115 mg/dL
C. 130–145 mg/dL
D. 165–180 mg/dL

A

d

38
Q

In which of the following conditions is glycosuria
most likely?
A. Addison’s disease
B. Hypothyroidism
C. Pregnancy
D. Hypopituitarism

A

c

39
Q

In addition to ascorbate, the glucose oxidase
reaction may be inhibited by which substance?
A. Acetoacetic acid (AAA)
B. ε-Aminocaproic acid
C. Creatinine
D. Azopyridium

A

a

40
Q

A positive glucose oxidase test and a negative test for reducing sugars indicates:
A. True glycosuria
B. False-positive reagent strip test
C. False-negative reducing test caused by ascorbate
D. Galactosuria

A

a

41
Q

A negative glucose oxidase test and a positive test for reducing sugars in urine indicates:
A. True glycosuria
B. A false-negative glucose oxidase reaction
C. The presence of a nonglucose reducing sugar such as galactose
D. A trace quantity of glucose

A

c

42
Q

In what condition may urinary ketone tests
underestimate ketosis?
A. Acidosis
B. Hemolytic anemia
C. Renal failure
D. Excessive use of vitamin C

A

a

43
Q

AAA is detected in urine by reaction with:
A. Sodium nitroprusside
B. o-Toluidine
C. m-Dinitrobenzene
D. m-Dinitrophenylhydrazine

A

a

44
Q

Nondiabetic ketonuria can occur in all of the
following except:
A. Pregnancy
B. Renal failure
C. Starvation
D. Lactate acidosis

A

b

45
Q

Which of the following statements regarding the classical nitroprusside reaction for ketones is true?
A. The reaction is most sensitive to acetone
B. Nitroprusside reacts with acetone, AAA, and
β-hydroxybutyric acid
C. It may be falsely positive in phenylketonuria
D. The reaction is recommended for diagnosing
ketoacidosis

A

c

46
Q

Hemoglobin in urine can be differentiated from
myoglobin using:
A. 80% ammonium sulfate to precipitate
hemoglobin
B. Sodium dithionite to reduce hemoglobin
C. o-Dianisidine instead of benzidine as the color
indicator
D. The dry reagent strip blood test

A

a

47
Q

Which statement about the dry reagent strip blood test is true?
A. The test is based on the reaction of hemoglobin
with peroxidase
B. Abnormal color may be absent from the urine when the reaction is positive
C. A nonhemolyzed trace is present when there
are 1–2 RBCs per high-power field
D. Salicylates cause a false-positive reaction

A

b

48
Q

Which of the following conditions is associated
with a negative blood test and an increase in urine urobilinogen?
A. Calculi of the kidney or bladder
B. Malignancy of the kidney or urinary system
C. Crush injury
D. Extravascular hemolytic anemia

A

d

49
Q

A moderate-positive blood test and trace protein test are seen on the dry reagent strip, and 11–20 red blood cells per high-power field are seen in the microscopic exam. These results are most likely caused by which of the following?
A. Transfusion reaction
B. Myoglobinuria
C. Intravascular hemolytic anemia
D. Recent urinary tract catheterization

A

d

50
Q

Which of the following results are discrepant?
A. Small amount of blood but negative protein
B. Moderate amount of blood but no RBCs in
microscopic exam
C. Negative blood but 6–10 RBCs/high-power
field (HPF)
D. Negative blood, positive protein

A

c

51
Q

Which of the following statements regarding the dry reagent strip test for bilirubin is true?
A. A positive test is seen in prehepatic, hepatic,
and posthepatic jaundice
B. The test detects only conjugated bilirubin
C. Standing urine may become falsely positive due to bacterial contamination
D. High levels of ascorbate will cause positive
interference

A

b

52
Q

Which of the following reagents is used to detect urobilinogen in urine?
A. p-Dinitrobenzene
B. p-Aminosalicylate
C. p-Dimethylaminobenzaldehyde
D. p-Dichloroaniline

A

c

53
Q

Which of the following statements regarding
urinary urobilinogen is true?
A. Diurnal variation occurs with highest levels seen in the early morning
B. High levels occurring with a positive bilirubin
test indicate obstructive jaundice
C. Dry reagent strip tests do not detect decreased levels
D. False-positive results may occur if urine is stored for more than 2 hours

A

c

54
Q

Which of the following statements regarding the test for nitrite in urine is true?
A. It detects more than 95% of clinically significant bacteriuria
B. Formation of nitrite is unaffected by the
urine pH
C. The test is dependent upon an adequate dietary nitrate content
D. A positive test differentiates bacteriuria from in vitro bacterial contamination

A

c

55
Q

Which statement about the dry reagent strip test for leukocytes is true?
A. The test detects only intact white blood
cells (WBCs)
B. The reaction is based upon the hydrolysis of
substrate by WBC esterases
C. Several antibiotics may give a false-positive
reaction
D. The test is sensitive to 2–3 WBCs per HPF

A

b

56
Q

Which of the following statements about
creatinine clearance is correct?
A. Dietary restrictions are required during the
24 hours preceding the test
B. Fluid intake must be restricted to below 600 mL
in the 6 hours preceding the test
C. Creatinine clearance is mainly determined by
renal tubular function
D. Creatinine clearance is dependent upon lean
body mass

A

d

57
Q

A male patient’s eGFR is 75 mL/min. This
indicates:
A. Normal glomerular filtration rate
B. The patient is uremic and will be hyperkalemic
C. Renal tubular dysfunction
D. Reduced glomerular filtration without uremia

A

d

58
Q

Which of the following tests is a specific measure of glomerular filtration?
A. p-Aminohippuric acid (PAH) clearance
B. Fishberg concentration test
C. Mosenthal dilution test
D. Cystatin C

A

d

59
Q

Which statement regarding urea is true?
A. Urea is 100% filtered by the glomeruli
B. Blood urea levels are independent of diet
C. Urea is not significantly reabsorbed by the
tubules
D. Urea excretion is a specific measure of glomerular function

A

a

60
Q

Given the following data, calculate the creatinine clearance.
Serum creatinine = 1.2 mg/dL;
urine creatinine = 100 mg/dL;
urine volume = 1.4 L/day;
body surface area = 1.80 m^2
A. 47 mL/min
B. 78 mL/min
C. 100 mL/min
D. 116 mL/min

A

b