7.1 Routine Physical and Biochemical Urine Tests Flashcards
Which statement regarding renal function is true?
A. Glomeruli are far more permeable to H2O and salt compared with 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 and urea
A. Glomeruli are far more permeable to H2O and salt compared with other capillaries
Which statement regarding normal salt and H2O handling by the nephron is correct?
A. The thick 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. The thick ascending limb of the tubule is highly permeable to salt but not H2O
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 less than 3.5 mmol/L
C. No substance can be excreted into urine at a rate that exceeds the glomerular filtration rate (GFR)
D. When tubular function is lost, the specific gravity (SG) of urine will be below 1.005
A. In salt deprivation, the kidneys will conserve sodium at the expense of potassium
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 to 8°C for up to 48 hours prior to plating
D. The sample may be held at 2°C to 8°C for up to 48 hours prior to plating
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. A midday sample is preferred when renal disease is suspected
C. Samples may be stored at room temperature for up to 2 hours
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
C. Deep yellow urine and yellow foam with bilirubin
Which of the following substances will cause urine to produce red fluorescence when examined under an ultraviolet lamp (360 nm)?
A. Myoglobin
B. Porphobilinogen (PBG)
C. Urobilin
D. Coproporphyrin
D. Coproporphyrin
Which of the following conditions is associated with normal urine color but produces red fluorescence when urine is examined with an ultraviolet (Wood) lamp?
A. Acute intermittent porphyria
B. Lead poisoning
C. Erythropoietic porphyria
D. Porphyria cutanea tarda
B. Lead poisoning
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
D. Serum, urine, and fecal tests may be needed for diagnosis
Which is the most common form of porphyria?
A. Erythropoietic porphyria
B. Acute intermittent porphyria
C. Variegate porphyria
D. Porphyria cutanea tarda
D. Porphyria cutanea tarda
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 reaction
D. Isotope dilution–MS
A. Watson-Schwartz test
A brown or black pigment in urine can be caused by:
A. Gantrisin (pyridium)
B. Phenolsulfonphthalein (PSP)
C. Rifampin
D. Melanin
D. Melanin
Urine that is dark red or port wine-colored may be caused by:
A. Lead poisoning
B. Porphyria cutanea tarda
C. Alkaptonuria
D. Hemolytic anemia
B. Porphyria cutanea tarda
Which of the following tests is affected least by standing or improperly stored urine?
A. Glucose
B. Protein
C. pH
D. Bilirubin
B. Protein
Which one of the following characteristics would be a reason for performing a microscopic examination of urinary sediment?
A. High volume
B. Color intensity
C. Turbidity
D. Specimen from a Foley catheter
C. Turbidity
Which of the following is appropriate when collecting a 24-hour urine sample for metanephrines?
A. Urine in the bladder is voided at the start of the test and added to the collection container
B. At 24 hours, any urine in the bladder is voided and discarded
C. All urine should be collected in a single container that is kept refrigerated
D. Ten milliliters of 1N sodium hydroxide should be added to the container before collection
C. All urine should be collected in a single container that is kept refrigerated
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
C. Defined as oliguria
Which of the following contributes to SG, but not to osmolality?
A. Protein
B. Salt
C. Urea
D. Glucose
A. Protein
Urine with an SG consistently between 1.002 and 1.003 indicates:
A. Acute glomerulonephritis
B. Renal tubular failure
C. Diabetes insipidus
D. Addison disease
C. Diabetes insipidus
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
C. Chronic renal failure
Which statement regarding methods for measuring SG is true?
A. Refractometry is the most accurate way to determine dissolved solute concentration
B. Colorimetric SG test results are falsely elevated when a large quantity of glucose is present
C. Colorimetric SG readings are falsely low when pH is alkaline
D. Refractometry should be performed before the urine is centrifuged
C. Colorimetric SG readings are falsely low when pH is alkaline
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. Ionic strength alters the pKa of a polyelectrolyte
Which statement regarding urine pH is true?
A. A high-protein diet promotes 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
C. Contamination should be suspected if urine pH is less than 4.5
In renal tubular acidosis, the pH of urine is:
A. Consistently acid
B. Consistently alkaline
C. Neutral
D. Variable, depending on diet
B. Consistently alkaline