Harr MLS Review Urinalysis and Body Fluids UPDATED ACTUAL Questions and CORRECT Answers
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Urinalysis and Body Fluids
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Urinalysis And Body Fluids
Harr MLS Review Urinalysis and Body
Fluids UPDATED ACTUAL Questions and
CORRECT Answers
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...
Harr MLS Review Urinalysis and Body
Fluids UPDATED ACTUAL Questions and
CORRECT Answers
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 - CORRECT ANSWER-
A. Glomeruli are far more permeable to H2O and salt than other capillaries
The formation of plasma ultrafiltrate depends upon high hydrostatic pressure and permeability of
the glomeruli. Aldosterone is released when afferent arterial pressure falls, and ADH is released
when plasma osmolality becomes too high. The collecting tubule reabsorbs sodium and secretes
potassium in response to aldosterone, and is permeable to H2O only in the presence of ADH.
The thick ascending limb is permeable to salt, but not to H2O or urea.
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 - CORRECT ANSWER- A The
ascending limb of the tubule is highly permeable to salt but not H2O
The tubules are able to concentrate the filtrate because the descending limb is highly permeable
to H2O and urea but not to salt, and the ascending limb is permeable to salt. Salt leaving the
ascending limb creates a hypertonic interstitium that forces H2O from the descending limb.
Renin is released in response to low hydrostatic pressure in the afferent arteriole, which
,stimulates the juxtaglomerular cells. ADH is released by the posterior pituitary in response to
high plasma osmolality.
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 - CORRECT
ANSWER- A. In salt deprivation, the kidneys will conserve sodium at the expense of
potassium
Sodium is a threshold substance, meaning that no sodium will be excreted in the urine until the
renal threshold (a plasma sodium concentration of approximately 120 mmol/L) is exceeded.
Potassium is not a threshold substance and will be secreted by the tubules even when plasma
potassium levels are low. Patients on diuretics or who have hypovolemia become hypokalemic
for this reason. Some substances (e.g., penicillin) can be excreted at a rate exceeding glomerular
filtration because the tubules secrete them. The tubules are responsible for concentrating the
filtrate in conditions of water deprivation and diluting it in conditions of water excess. When
tubular function is lost, salt and water equilibrate by passive diffusion and the specific gravity of
the urine becomes the same as the plasma, approximately 1.010.
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 - CORRECT
ANSWER- D. The sample may be held at 2°C-8°C for up to 48 hours prior to plating
Urine specimens should be plated and incubated within 2 hours of collection (some labs use a 1-
hour time limit), and within 24 hours if the sample is refrigerated at 2°C-8°C immediately
following collection. No additives are permitted when urine is collected for culture.
,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 - CORRECT
ANSWER- C. Samples may be stored at room temperature for up to 2 hours
The first morning voided sample is the most sensitive for screening purposes because formed
elements are concentrated, but random samples are satisfactory because glomerular bleeding,
albuminuria, and cast formation may occur at any time. Preservative tablets should be avoided
because they may cause chemical interference with some
dry reagent strip and turbidimetric protein tests. Changes in glucose, bilirubin, and urobilinogen
can occur within 30 minutes of collection. Therefore, samples should be refrigerated if not tested
within 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 - CORRECT ANSWER- C. Deep yellow urine and
yellow foam with bilirubin
Homogentisic acid causes dark brown or black-colored urine. Myoglobin causes a red to red-
brown color in urine, and biliverdin causes a green or yellow-green color. In addition to
metabolic diseases and renal disease, abnormal color can be caused by drugs (e.g., Gantrisin),
dyes excreted by the kidneys (e.g., PSP), and natural or artificial food coloring (e.g., beets).
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 - CORRECT ANSWER- Coproporphyrin
Myoglobin causes a positive test for blood but does not cause urine to fluoresce. PBG causes
urine to become dark (orange to orange-brown) on standing but does not fluoresce. Uroporphyrin
and coproporphyrin produce red or orange-red fluorescence. Unlike hemoglobin, porphyrins lack
peroxidase activity. Urobilin is an oxidation product of urobilinogen. It turns the urine orange to
orange-brown but does not produce fluorescence.
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 - CORRECT ANSWER- B. Lead poisoning
Lead poisoning blocks the synthesis of heme, causing accumulation of PBG and coproporphyrin
III in urine. However, uroporphyrin levels are not sufficiently elevated to cause red pigmentation
of the urine. There is sufficient coproporphyrin to cause a positive test for fluorescence. Acute
intermittent porphyria produces increased urinary delta-aminolevulinic acid (∆-ALA), and PBG.
The PBG turns the urine orange to orange-brown upon standing. Erythropoietic porphyria and
porphyria cutanea tarda produce
large amounts of uroporphyrin, causing the urine to be red or port wine colored.
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 - CORRECT ANSWER- D.
Serum, urine, and fecal tests may be needed for diagnosis
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