Evaluative Exam (AUBF)

Question 1

Why is the first-voided morning urine
specimen the most desirable specimen for
routine urinalysis?

A. Most dilute specimen of the day and
therefore any chemical compounds
present will not exceed the detectability
limits of the reagent strips
B. Least likely to be contaminated with
microorganisms because the bladder is
a sterile environment
C. Most likely to contain protein because
the patient has been in the orthostatic
position during the night
D. Most concentrated specimen of the
day and therefore it is more likely that
abnormalities will be detected

Answer 1

D. The first-voided morning urine specimen is the most desirable for chemical and microscopic
analysis because it is the most concentrated specimen of the day

Question 2

The physical characteristic of color
is assessed when a routine urinalysis
is performed. What substance is
normally found in urine that is principally
responsible for its yellow coloration?
A. Bilirubin
B. Melanin
C. Carotene
D. Urochrome

Answer 2

D. Urochrome, a yellow-brown pigment derived
from urobilin, is principally responsible for the
yellow coloration of normal urine. Urochrome is
excreted at a constant rate, showing no diurnal
variation.

Question 3

In certain malignant disorders, what
substance is found in the urine that turns
the urine dark brown or black on exposure
of the urine to air?

A. Urobilinogen
B. Indican
C. Melanin
D. Porphyrin

Answer 3

C. Melanin, a substance derived from tyrosine,
is responsible for the pigmentation of the eyes,
skin, and hair. In some malignancies, known
as melanomas, the tumor or mole takes on a darkly pigmented appearance because of the melanin present.

Question 4

What is the expected pH range of a freshly
voided urine specimen?
A. 3.5-8.0
B. 3.5-9.0
C. 4.0-8.5
D. 4.5-8.0

Answer 4

D. pH is a representative symbol for the hydrogen ion concentration. The kidney plays an
important role in the maintenance of the acidbase balance of body fluids by either excreting
or retaining hydrogen ions.

Question 5

Urine specimens should be analyzed as
soon as possible after collection. If urine
specimens are allowed to stand at room
temperature for an excessive amount of
time, the urine pH will become alkaline
because of bacterial decomposition of
A. Protein
B. Urea
C. Creatinine
D. Ketones

Answer 5

B. At room temperature, the amount of bacteria
present in a urine sample will increase. The bacteria are capable of metabolizing the urinary urea to ammonia

Question 6

Which term is defined as a urine volume
in excess of 2000 mL excreted over a
24-hour period?
A. Anuria
B. Oliguria
C. Polyuria
D. Hypersthenuria

Answer 6

C. On the average, a normal adult excretes
1200-1500 mL of urine daily. “Polyuria” is a
term used to describe the excretion of a urine
volume in excess of 2000 mL/day. In oliguria,
the daily urine excretion is less than 500 mL,
and in anuria the urine formation is completely
suppressed. Hypersthenuria refers to urines of
any volume containing increased levels of dissolved solute.

Question 7

The reagent test strips used for the
detection of protein in urine are most
reactive to

A. Albumin
B. Hemoglobin
C. Alpha-globulins
D. Beta-globulins

Answer 7

A. In healthy individuals the amount of protein
excreted in the urine should not exceed 150
mg/24 hr. When protein is present in the urine,
the colorimetric reagent test strips change color,
indicating a semiquantification of the amount of
protein present. Serum proteins are classified as
being albumin or globulin in nature, and the type
of protein excreted in the urine is dependent on
the disorder present. Although the strip test is a
rapid screening method for the detection of urinary protein, it must be noted that this method is
more sensitive to the presence of albumin in the
specimen than to the presence of globulin, Bence
Jones protein, or mucoprotein.

Question 8

A urine specimen that exhibits yellow
foam on being shaken should be suspected
of having an increased concentration of
A. Protein
B. Hemoglobin
C. Bilirubin
D. Nitrite

Answer 8

C. Normal urine does not foam on being shaken.
However, urine containing bilirubin will exhibit
yellow foaming when the specimen is shaken. In
fact, the foam test was actually the first test for
bilirubin, before the development of the chemical
tests. If the shaken specimen shows a white
foam, increased urine protein can be suspected

Question 9

How should controls be run to ensure the
precision and accuracy of the reagent test
strips used for the chemical analysis of
urine?
A. Positive controls should be run on a
daily basis and negative controls when
opening a new bottle of test strips.
B. Positive and negative controls should
be run when the test strips’ expiration
date is passed.
C. Positive and negative controls should
be run on a daily basis.
D. Positive controls should be run on a
daily basis and negative controls on a
weekly basis.

Answer 9

C. For quality control of reagent test strips, it is
recommended that both positive and negative
controls be used daily. It is necessary that any
deterioration of the strips be detected in order to
avoid false-positive or false-negative results.

Question 10

10. The colorimetric reagent strip test for
    protein is able to detect as little as 5-20 nig
    of protein per deciliter. What may cause a
    false-positive urine protein reading?
    A. Uric acid concentration is greater than
    0.5 g/day.
    B. Vitamin C concentration is greater
    than 0.5 g/day.
    C. Glucose concentration is greater than
    130mg/day.
    D. pH is greater than 8.0.

Answer 10

D. The principle of the reagent strip method for
the detection of protein in urine is based on a
color change in an indicator system, such as
tetrabromophenol blue, that is buffered to pH 3.
The buffering capacity of the strip is sufficient
provided that the urine pH does not exceed 8.0.
Within the normal urine pH range of 4.5-8.0, a
change in color in the reagent strip is an indication of the presence of protein in the urine. With
a urine pH greater than 8, the buffering capacity
of the strip may be exceeded, and a false-positive color change in the impregnated area will
reflect the pH of the urine rather than the presence of protein

Question 11

11. “Isosthenuria” is a term applied to a series
    of urine specimens from the same patient
    that exhibit a
    A. Specific gravity of exactly 1.000
    B. Specific gravity less than 1.007
    C. Specific gravity greater than 1.020
    D. Fixed specific gravity of approximately 1.010

Answer 11

D. “Isosthenuria” is a term applied to a series of urine specimens that exhibit a fixed specific gravity of approximately 1.010. In isosthenuria there is little, if any, variation of the specific gravity between urine specimens from the same patient. This condition is abnormal and denotes the presence of severe renal damage in which both the diluting ability and the concentrating ability of the kidneys have been severely affected

Question 12

A urine specimen is tested by a reagent
strip test and the sulfosalicylic acid test to
determine whether protein is present. The
former yields a negative protein, whereas
the latter results in a reading of 2+
protein. Which of the following statements
best explains this difference?
A. The urine contained an excessive
amount of amorphous urates or
phosphates that caused the turbidity
seen with the sulfosalicylic acid test.
B. The urine pH was greater than 8,
exceeding the buffering capacity
of the reagent strip, thus causing
a false-negative reaction.
C. A protein other than albumin must be
present in the urine.
D. The reading time of the reagent strip
test was exceeded (the reading being
taken at 2 minutes), causing a false-negative reaction to be detected.

Answer 12

C. When globulin, mucoprotein, or Bence Jones protein is present in a urine specimen, the reagent strip test may give a negative result because the strip is more sensitive to the presence of albumin than to the presence of other proteins in urine. However, the sulfosalicylic acid (SSA) test is able to detect not only albumin but also globulin, mucoprotein, and Bence Jones protein in a specimen. Therefore, it can be seen that a negative reagent strip test result for protein but a positive sulfosalicylic acid test result is possible when the protein present is some protein other than albumin. For this reason the sulfosalicylic acid test is run as a test for urinary protein if the presence of abnormal proteins is suspected.

Question 13

Which of the following is the major
organic substance found in urine?

A. Sodium
B. Potassium
C. Glucose
D. Urea

Answer 13

D. Although sodium is the major inorganic molecule found in urine, urea is the major organic
molecule excreted. Urea is a waste product of
protein/amino acid metabolism. Its level in a normal 24-hour urine with a glomerular filtration
rate of 125 mL/min would be 400 mmol/day.
Glucose excretion will average less than 1 mmol/
day. The excretion of the inorganic molecules
sodium and potassium would be 130 and 70 mmol/
day, respectively

Question 14

Each of the following is included in the
quality assurance program for a urinalysis
laboratory. Which one represents a
preanalytical component of testing?
A. Setting collection guidelines for
24-hour urines
B. Setting a maintenance schedule for
microscopes
C. Reporting units to be used for crystals
D. Requiring acceptable results for
control specimens before any patient
results are reported out

Answer 14

A. Preanalytical components of laboratory testing include all variables that can affect the
integrity or acceptability of the patient specimen
prior to analysis, such as correct collection technique. Analytical factors affect the actual analysis of the specimen (temperature, condition of
equipment, timing, presence of interfering substances). Postanalytical factors affect the final
handling of the results generated (reporting
units, critical values, acceptability of quality
control).

Question 15

The presence of ketone bodies in urine
specimens may be detected by use of a
reagent strip impregnated with sodium
nitroprusside. This strip test is sensitive
to the presence of
A. Acetoacetic acid and betahydroxybutyric acid
B. Acetoacetic acid and acetone
C. Diacetic acid and beta-hydroxybutyric
acid
D. Beta-hydroxybutyric acid and acetone

Answer 15

B. Under normal metabolic conditions, the
body metabolizes fat to carbon dioxide and
water. With inadequate carbohydrate intake, as
with dieting and starvation, or with inadequate
carbohydrate metabolism, as with diabetes mellitus, there is an increased utilization of fat.
Because of this increased fat metabolism, the
body is unable to completely degrade the fat,
resulting in a buildup of intermediary products
known as ketone bodies. The term “ketone bodies” is used collectively to denote the presence
of acetoacetic acid, beta-hydroxybutyric acid,
and acetone. Reagent test strips impregnated
with sodium nitroprusside are able to detect the
presence of acetoacetic acid and acetone in urine
specimens. Although beta-hydroxybutyric acid
accounts for approximately 78% of the total
ketones, it is not detected by the sodium nitroprusside test.

Question 16

A routine urinalysis is performed on a
young child suffering from diarrhea. The
reagent test strip is negative for glucose
but positive for ketones. These results may
be explained by which of the following
statements?

A. The child has Type 1 diabetes mellitus.
B. The child is suffering from lactic
acidosis, and the lactic acid has falsely
reacted with the impregnated reagent
area for ketones.
C. The child is suffering from increased
catabolism of fat because of decreased
intestinal absorption.
D. The reagent area for ketones was read
after the maximum reading time
allowed.

Answer 16

C. Although a positive result on a urine test for
ketones is most commonly associated with
increased urinary glucose levels, as in diabetes
mellitus, other conditions may cause the urine
ketone test to show positive results while the
urine glucose test shows negative results. In
young children, a negative glucose reaction
accompanied by a positive ketone reaction is
sometimes seen. Ketones in the urine may be
seen when a child is suffering from an acute
febrile disease or toxic condition that is accompanied by vomiting or diarrhea. In these cases,
because of either decreased food intake or
decreased intestinal absorption, fat catabolism is
increased to such an extent that the intermediary
products, known as ketone bodies, are formed
and excreted in the urine.

Question 17

The principle of the colorimetric reagent
strip test for hemoglobin is based on the
peroxidase activity of hemoglobin in
catalyzing the oxidation of a dye with
peroxide to form a colored compound.
This method may yield false-positive
results for the presence of hemoglobin
when the urine specimen contains

A. Ascorbic acid
B. Tetracycline
C. Myoglobin
D. Nitrite

Answer 17

C. The colorimetric reagent strip test for the
detection of hemoglobin in urine utilizes a
buffered test zone impregnated with a dye and
organic peroxide. The peroxidase activity of
hemoglobin catalyzes the oxidation of the dye
with peroxide to form a colored compound. Like
hemoglobin, myoglobin also has a peroxidase
activity and, when present in a urine specimen,
myoglobin will react, yielding false-positive
results. In the presence of large amounts of
ascorbic acid, antibiotics containing ascorbic
acid as a preservative, formaldehyde, or nitrite,
the urine reaction may be inhibited, causing
false-negative results.

Question 18

A reagent test strip impregnated with
a diazonium salt such as diazotized
2,4-dichloroaniline may be used to
determine which analyte?

A. Glucose
B. Ketone
C. Hemoglobin
D. Bilirubin

Answer 18

D. Bilirubin is a compound that is formed as a
result of hemoglobin breakdown. The majority
of bilirubin in the blood is bound to albumin and
is known as unconjugated bilirubin. Because
unconjugated bilirubin is not water soluble, it
may not be excreted in the urine. The remainder
of the bilirubin in the blood has been processed
by the liver. In the liver, the bilirubin is conjugated with glucuronic acid or sulfuric acid. This
conjugated bilirubin is water soluble, and it is
this portion that is excreted in increased amounts
in the urine in some hepatic and obstructive biliary tract diseases. The presence of conjugated
bilirubin in a urine specimen may be detected by
use of the reagent test strips. The test strips are
impregnated with a diazonium salt, such as diazotized 2,4-dichloroaniline, which forms a purplish azobilirubin compound with bilirubin.

Question 19

Which of the following will contribute to a
specimen’s specific gravity if it is present
in a person’s urine?

A. 50-100 RBC/hpf
B. 85 mg/dL glucose
C. 3+ amorphous phosphates
D. Moderate bacteria

Answer 19

B. Only dissolved solutes affect specific gravity
(e.g., glucose). Cells, mucus, crystals, or any
other formed elements will have no effect, regardless of concentration. If the reagent strip method is used, it should be noted that only dissolved ions
will contribute to specific gravity results. Thus
glucose would not affect reagent strip results at
any concentration. In such instances as diabetes
mellitus, with urine glucose levels over 2 g/dL,
there may be a discrepancy between specific gravity results obtained with a reagent strip method
versus using a refractometer, because such glucose levels are known to increase refractometer
results, thus requiring correction.

Question 20

With infections of the urinary system,
white blood cells are frequently seen in
the urine sediment. What type of white
blood cell is seen the most frequently in
urine sediment?

A. Eosinophil
B. Lymphocyte
C. Monocyte
D. Neutrophil

Answer 20

D. The majority of renal and urinary tract diseases are characterized by an increased number
of neutrophilic leukocytes in the urine. To identify correctly any white blood cells present in a
urine specimen, it is necessary to examine the
specimen as soon as possible after collection.
This is necessary because leukocytes tend to
lyse easily when exposed to either hypotonic or
alkaline urine.

Question 21

A random urine is collected from a patient
and the results obtained are as follows:
urine albumin =16 mg/dL and urine
creatinine = 140 mg/dL. These findings
are consistent with

A. Microalbuminuria
B. Macroalbuminuria
C. Nephrotic syndrome
D. Obstructive jaundice

Answer 21

A. The ratio of urine albumin to creatinine in a
random specimen is commonly used to evaluate
microalbuminuria, especially in patients with diabetes mellitus. This patient’s ratio is 114 mg albumin per gram creatinine. The American Diabetes
Association defines microalbuminuria as between
30 and 299 mg/g. Values greater than 299 mg/g
would be “macroalbuminuria.” Nephrotic syndrome is characterized by excretion of albumin
in excess of 3.5 grams per day. Patients with
obstructive jaundice will usually not experience
proteinuria

Question 22

To detect more easily the presence of casts
in urine sediments, which microscopic
method can be used?

A. Fluorescent microscopy
B. Phase-contrast microscopy
C. Polarized microscopy
D. Brightfield microscopy

Answer 22

B. To better diagnose renal and urinary tract
diseases, it is necessary to examine urinary sediment carefully by the most appropriate microscopic method available. Formed elements in
the urine, such as cells and casts, are more easily differentiated by the use of phase-contrast
microscopy. This is especially true for the identification of the more translucent elements such as
the hyaline casts. Phase microscopy tends to
enhance the outline of the formed elements,
allowing them to stand out and be more easily
distinguished.

Question 23

Which substance found in urinary
sediment is more easily distinguished
by use of polarized microscopy?

A. Lipids
B. Casts
C. Red blood cells
D. Ketone bodies

Answer 23

A. Fatty materials in urinary sediment may be
identified by means of staining techniques using
Sudan III and oil red O or by means of polarized
microscopy. Polarized microscopy is especially
useful when the composition of fatty casts, fatty
droplets, or oval fat bodies is primarily cholesterol. When cholesterol molecules are exposed
to polarized microscopy, the effect is such that a
Maltese cross formation becomes visible, simplifying the identification process. Casts and red
blood cells may be better visualized using phase-contrast microscopy. Ketone bodies will be soluble and, therefore, not seen in a urine sediment

Question 24

“Glitter cell” is a term used to describe
a specific type of

A. Ketone body
B. Oval fat body
C. Fatty droplet
D. Neutrophil

Answer 24

D. When neutrophils are exposed to hypotonic
urine, their physical appearance becomes altered.
Under hypotonic conditions, the neutrophils
tend to swell and the cytoplasmic granules contained within the cells exhibit Brownian movement. This Brownian movement of the granules
causes the neutrophilic contents to refract in
such a way that the cells appear to glitter—thus
the name “glitter cells.”

Question 25

The final phase of degeneration that granular casts undergo is represented by which of the following casts? A. Fine B. Coarse C. Cellular D. Waxy

Answer 25

D. Waxy casts represent the final phase of granular cast degeneration. As the fine granules of the granular casts lyse, highly refractive, smooth, blunt-ended waxy casts are formed. When waxy casts are found in the urine sediment, the implication is that there is nephron obstruction caused by tubular inflammation and degeneration.

Question 26

A 40-year-old female patient with a history of kidney infection is seen by her physician because she has felt lethargic for a few weeks. She has decreased frequency of urination and a bloated feeling. Physical examination shows periorbital swelling and general edema, including a swollen abdomen. Significant urinalysis results show the following: color = yellow; appearance = cloudy/frothy; specific gravity = 1.022;pH = 7.0; protein = 4+; 0-3 WBC/hpf; 0-1 RBC/hpf; 0-2 renal epithelial cells/hpf; 10-20 hyaline casts/lpf; 0-1 granular casts/lpf; 0-1 fatty casts/lpf; occasional oval fat bodies. Her serum chemistries show significantly decreased albumin, increased urea nitrogen, and increased creatinine. These findings suggest which condition? A. Multiple myeloma B. Glomerulonephritis C. Nephrotic syndrome D. Chronic renal failure

Answer 26

C. Nephrotic syndrome is suggested by the increased urine protein (with serum albumin significantly decreased), the hyaline and fatty casts, and the presence of oval fat bodies. The patient's symptoms of periorbital swelling and edema reflect the loss of oncotic pressure because of the excretion of albumin. Its loss from the vascular compartment will induce plasma water movement into the tissue spaces. Glomerulonephritis will have many more red blood cells, including red blood cell casts. Multiple myeloma will not show increased urine albumin but rather immunoglobulin light chains. Chronic renal failure will have multiple types of casts present (hyaline, granular, cellular, waxy, fatty).

Question 27

A 47-year-old female patient with controlled type 2 diabetes mellitus complains of urinary frequency and burning. She provides a first-morning, clean-catch specimen. Results show color = yellow; appearance = cloudy; pH = 6.5; a representative microscopic high-power field is shown in Color Plate 46B. Which of the following is true for this patient? A. The number of bacteria seen would result in a positive nitrite. B. The major formed elements are white blood cells and yeast. C. The type and number of epithelial cells suggest incorrect sample collection. D. The red blood cells would be sufficient to give a positive blood result on the reagent strip

Answer 27

B. There are minimal bacteria present in Color Plate 46B. Both budding yeast and white blood cells predominate this microscopic field. Patients with diabetes mellitus are prone to such yeast infections because of the increased glucose in their urine. The epithelial cells visualized in this field are transitional and not squamous

Question 28

Alkaptonuria, a rare hereditary disease, is characterized by the urinary excretion of A. Alkaptone B. Phenylalanine C. 5-Hydroxyindole acetic acid D. Homogentisic acid

Answer 28

D. Alkaptonuria is a rare hereditary disease that is characterized by excessive urinary excretion of homogentisic acid. This acid, the product of phenylalanine and tyrosine metabolism, accumulates in urine because of a deficiency in the enzyme homogentisic acid oxidase, which normally catalyzes the oxidation of homogentisic acid to maleyl acetoacetic acid.

Question 29

A 22-year-old female clinical laboratory student performs a urinalysis on her own urine as part of a lab class. Significant results include: color = yellow; appearance = cloudy; pH = 7.5; nitrite = positive; leukocyte esterase - 2+; 25^0 WBC/hpf; 0-3 RBC/hpf; 2-5 squamous epithelial cells/hpf; moderate bacteria. All other chemistries and microscopic results were normal. These findings suggest A. Glomerulonephritis B. Upper urinary tract infection C. Lower urinary tract infection D. Nephrolithiasis

Answer 29

C. This student has a lower urinary tract infection (UTI), also known as cystitis. The major distinguishing features between upper and lower UTI include the presence of protein and casts in an upper UTI and not in a lower UTI.

Question 30

Metastatic carcinoid tumors arising from the enterochromaffin cells of the gastrointestinal tract are characterized by increased excretion of urinary A. Serotonin B. 5-Hydroxytryptophan C. Homogentisic acid D. 5-Hydroxyindole acetic acid

Answer 30

D. The intestinal enterochromaffin cells, sometimes called the argentaffin cells, produce a substance known as serotonin from the amino acid tryptophan.

Question 31

Some clinical conditions are characterized by unique urinalysis result patterns. Which of the following shows such a relationship? A. Nephrotic syndrome: positive protein on reagent strip, negative protein with sulfosalicylic acid B. Intensive dieting: increased ketones, negative glucose C. Multiple myeloma: positive protein by both reagent strip and sulfosalicylic acid D. Cystitis: positive nitrite and protein

Answer 31

B. Because of increased lipid metabolism in long-term, intensive dieting, ketone body formation will increase. Blood glucose levels in such patients will be normal or decreased.

Question 32

Nitrite in a urine specimen suggests the presence of A. White blood cells B. Red blood cells C. Bacteria D. Yeasts

Answer 32

C. Bacteria of the Enterobacter, Citrobacter, Escherichia, Proteus, Klebsiella, and Pseudomonas species produce enzymes that catalyze the reduction of nitrate, a substance normally found in urine, to nitrite.

Question 33

If a fasting plasma glucose level of 100 mg/dL is obtained on an individual, what is the expected fasting cerebrospinal fluid (CSF) glucose level in mg/dL? A. 25 B. 50 C. 65 D. 100

Answer 33

C. Cerebrospinal fluid (CSF) is a clear, colorless liquid that may be described as a modified ultrafiltrate of blood. Both active transport and passive diffusion are involved in the passage of glucose from the blood into the CSF.

Question 34

A 35-year-old man has just experienced severe crush injuries sustained in a car accident. He has a broken pelvis and right femur and has numerous abrasions and contusions. A random urinalysis specimen shows a brown color and clear appearance. pH is 6.0, protein is 1 + , and blood is 3+. There is, however, only 0-1 RBC/hpf, along with 0-3 WBC/hpf. Casts found include hyaline (0-2/lpf) and granular (0-1/Ipf). Other urine results are normal. Which of the following is true about this patient? A. The positive blood result is from a hemolytic anemia. B. The bilirubin result should have also been positive for this patient. C. Rhabdomyolysis may be a cause for the discrepant chemical/microscopic blood findings. D. The bone crushing led to the increased protein result

Answer 34

C. In addition to hemoglobin, the muscle protein myoglobin can cause a positive blood result in chemical reagent strip testing. Both hemoglobin and myoglobin possess pseudoperoxidase activity detected by the "blood" chemistry test. Muscle-crushing injuries (rhabdomyolysis) will release myoglobin from the muscle. The myoglobin, being a small molecule, is readily excreted by the kidneys. Myoglobinuria can lead to acute renal failure. Myoglobin can be distinguished from hemoglobin in urine by an ammonium sulfate screening test. Myoglobin will remain soluble in 80% ammonium sulfate and give a positive filtrate blood reaction after the precipitation of hemoglobin. The patient's pathology involves neither red blood cells nor bilirubin. The severe stress may be responsible for both the urine protein and granular cast results.

Question 35

A 67-year-old male has routine testing done and shows an estimated glomerular filtration rate (eGFR) of 42 mL/min/1.73 m2. Which of the following is true for this patient? A. This test requires a 24-hour urine collection. B. The patient does not have chronic kidney damage, based on these results. C. Similar results would be obtained using the Cockgroft-Gault formula. D. The patient is in Stage 3 chronic kidney damage

Answer 35

D. The eGFR calculation is based on the "modification of diet and renal disease" formula recommended by the American Kidney Foundation. It does not use a urine sample at all, but instead requires only a serum creatinine and the patient's age, gender, and race. Values less than 60 mL/ min/1.73 m2 are considered abnormal and need to be followed up. This patient's value places him in stage 3 kidney damage (35-59 mL/min/1.73 m2). This calculation is considered more accurate than the Cockgroft-Gault formula, but there are limitations based on the standardization of the creatinine method used.

Question 36

Which is true about the formed element shown in Color Plate 47 *? A. May be found in normal alkaline urine B. Associated with renal pathology C. Characteristic of glomerulonephritis D. Associated with lung pathology

Answer 36

A. Normal alkaline (or neutral) urine may contain triple phosphate crystals, as seen in Color Plate 47 *. These crystals can be identified by the characteristic "coffin lid" appearance. They usually do not indicate any pathology.

Question 37

The major formed element in the highpower field shown in Color Plate 48 * is most likely a A. Granular cast B. Hyaline cast C. Waxy cast D. Fiber artifact

Answer 37

D. Refer to Color Plate 48 *. The fringed appearance at the one end of the major formed element strongly suggests that this is a fiber artifact, most likely placed in the sample at the time of collection. Casts, taking the shape of the tubule within which they are formed, will not have such a fringed end.

Question 38

Which of the following is true about the final concentrating of urine in the kidney? A. The distal convoluted tubule, through active transport, reabsorbs water. B. Water is reabsorbed under the direct influence of angiotensin II. C. Vasopressin controls the collecting duct reabsorption of water. D. Water reabsorption is influenced by urine filtrate levels of potassium.

Answer 38

C. The distal convoluted tubule and collecting duct provide water reabsorption through the action of antidiuretic hormone (vasopressin). The renin-angiotensin-aldosterone system is responsible for sodium reabsorption by the distal and collecting tubules. Decreased plasma volume leads to pressure alterations detected by receptors located in the kidney's juxtaglomerular apparatus and the right atrium of the heart. These changes trigger the production of renin and antidiuretic hormone, respectively.

Question 39

If a urine specimen is left standing at room temperature for several hours, which of the following changes may occur? A. Multiplication of bacteria B. An increase in the glucose concentration C. Production of an acid urine D. Deterioration of any albumin present

Answer 39

A. Only freshly voided urine specimens should be used for urinalysis testing. If the specimen cannot be examined within 1 hour after collection, it should be refrigerated to help preserve the integrity of the specimen. When urine is left standing at room temperature for an excessive period, multiplication of bacteria will occur. The bacteria are capable of converting urea in the urine to ammonia, causing the urine to become more alkaline. Loss of carbon dioxide from the specimen will also contribute to the alkalinization of the urine. Constituents such as glucose, bilirubin, and urobilinogen will also be lost from the specimen.

Question 40

The formed element shown in Color Plate 49B would usually be found in the patient's urine along with which soluble biochemicals? A. Phenylalanine and tyrosine B. Ornithine and arginine C. Isoleucine and leucine D. Acetoacetic acid and B--hydroxy-butyric acid

Answer 40

B. The presence of cystine crystals in a patient sample is always a cause for immediate notification of the physician. Cystinuria is an autosomal recessive disorder characterized by the inability to reabsorb the amino acids cystine, lysine, arginine, and ornithine in either the renal tubules or the intestine. Cystine will crystallize in acid pH more readily than the other amino acids. Tyrosine forms needle-shaped crystals whereas leucine will appear round and oily with concentric rings. Isoleucine and phenylalanine will not form crystals in the urine. Acetoacetate and (3- hydroxybutyric acid are two ketone bodies that will be soluble in the sample and give a positive reaction with nitroprusside.

Question 41

A 13-year-old ice skater is having her routine physical before the school year. Her first morning urinalysis results include color = straw; appearance = hazy; pH = 6.0; protein = trace; a representative microscopic high-power field is shown in Color Plate 50B. All other chemical results were normal. The major formed elements are and suggest. A. Hyaline casts and waxy casts; nephrotic syndrome B. Mucus and fibers; no pathology C. Granular casts and red blood cells; glomerulonephritis D. Hyaline casts and mucus; normal sediment

Answer 41

D. The major formed elements in Color Plate 50B are hyaline casts and mucus fibers, which are normal in the numbers shown in this field. Waxy casts will appear yellowish with characteristic serrated edges. There are no obvious granules in the casts shown, and red blood cells are not present.

Question 42

Phenylketonuria may be characterized by which of the following statements? A. It may cause brain damage if untreated. B. It is caused by the absence of the enzyme, phenylalanine oxidase. C. Phenylpyruvic acid excess appears in the blood. D. Excess tyrosine accumulates in the blood.

Answer 42

A. Phenylketonuria is inherited as an autosomal recessive trait that manifests itself in the homozygous form. The basis for the disease lies in the fact that the enzyme phenylalanine hydroxylase, which is needed for the conversion of phenylalanine to tyrosine, is absent. Because of this enzyme deficiency, phenylalanine levels rise in the blood, with increased amounts of phenylpyruvic acid and other derivatives being excreted in the urine. If the disease is detected at an early stage, mental retardation may be avoided by restricting the dietary intake of phenylalanine

Question 43

What condition is suggested by the number of the formed element that predominates in the high-power field of Color Plate 51? A. Glomerulonephritis B. Improperly collected specimen C. Pyelonephritis D. Normal sample

Answer 43

D. Color Plate 51B demonstrates sperm and calcium oxalate crystals. Both formed elements are found in correctly collected normal urines from either gender. Calcium oxalate seen here is the dehydrate form. The monohydrate form will appear oval or dumbbell shaped. Neither formed element is usually associated with pathology.

Question 44

Xanthochromia of cerebrospinal fluid (CSF) samples may be due to increased levels of which of the following? A. Chloride B. Protein C. Glucose D. Magnesium

Answer 44

B. A variety of substances in CSF specimens have been associated with a xanthochromic appearance. Among those substances are oxyhemoglobin, carotenoids, bilirubin, and protein. The appearance of the specimen by itself is not usually specific for a particular disease state, but it may provide useful information in comparison with other findings. Glucose, magnesium, and chloride do not contribute to the color of the specimen.

Question 45

Which of the following will be characterized by an increased number of the urinary component seen in Color Plate 52? A. Acute glomerulonephritis B. Biliary tract obstruction C. Contamination from vaginal discharge D. Nephrotic syndrome

Answer 45

A. Refer to Color Plate 52B. Erythrocytes or red blood cells (RBCs) occur in small numbers (0-2/hpf) in a normal urine. Using brightfield microscopy, unstained RBCs appear as colorless discs with an average size of 7 jam in diameter. Increased or large numbers of RBCs are commonly seen with acute glomerulonephritis, renal calculi, acute infections, and menstrual contamination. The nephrotic syndrome is characterized by heavy proteinuria, oval fat bodies, renal tubular epithelial cells, casts, and waxy and fatty casts. Biliary tract obstruction will show palecolored stools, whereas vaginal discharge contamination may introduce increased numbers of white blood cells.

Question 46

To determine amniotic fluid contamination with maternal urine, which of the following measurements could be used? A. Creatinine concentration B. Delta absorbance at 410 nm C. Albumin/globulin ratio D. Lactate dehydrogenase

Answer 46

A. Because there may be technical problems associated with amniocentesis, contamination with maternal urine should be considered in evaluating specimens submitted for amniotic fluid analysis. Urinary concentrations of creatinine and urea nitrogen are anywhere from 10 to 50 times the amniotic fluid concentrations, and an increased concentration of either in the amniotic fluid would be sensitive indicators of urinary contamination. Measurements of albumin, total protein, or lactate dehydrogenase would be of little use for this purpose because their relative concentrations in urine and amniotic fluid are not predictably different. A delta absorbance at 410 nm would be used to assess the presence of bilirubin in the sample, as in assessment of erythroblastosis fetalis.

Question 47

With the development of fetal lung maturity, which of the following phospholipid concentrations in amniotic fluid significantly and consistently increases? A. Sphingomyelin B. Phosphatidyl ethanolamine C. Phosphatidyl inositol D. Phosphatidyl choline

Answer 47

D. The alveolar concentrations of the various phospholipids (surfactants) change during fetal lung development, and because these changes are reflected directly in the amniotic fluid, a number of investigations have shown that analysis of the fluid can provide good predictive information for the development of respiratory distress syndrome in the newborn. The concentrations of sphingomyelin and phosphatidyl inositol increase until about 32-34 weeks of gestation and then decline. Conversely, lecithin (phosphatidyl choline) and phosphatidyl glycerol concentrations increase rapidly after 32-34 weeks of gestation, and their concentrations relative to those of the other phospholipids are useful in assessing the development of fetal lung maturity

Question 48

A patient has been diagnosed with an upper gastrointestinal bleed. Which of the following would be characteristic for this condition? A. Brown stool with streaks of bright red B. Stool with lack of brown color ("clay-colored") C. Stool with a much darker brown/black color D. Yellow stool with increased mucus

Answer 48

C. The hemoglobin released from red blood cells in an upper gastrointestinal bleed will have time to become denatured and oxidized as it travels the entire intestinal tract. This will make the stool become much darker in color by the time the hemoglobin is excreted. Clay-colored stools will result from an obstruction of the biliary duct, preventing bilirubin from entering the intestines to be converted into urobilinogen and then into urobilin. Stools with red streaks are more likely to result from a lower gastrointestinal bleed, as from the colon. Increased mucus will be associated with intestinal inflammation

Question 49

A pleural effusion is found to have 3000 white blood cells per microliter and 5 g/dL total protein. From this it can be determined that the patient's effusion is A. A transudate B. An exudate C. Noninflammatory D. Hemorrhagic

Answer 49

B. Effusions can be transudates or exudates, and the distinguishing characteristics are cell number and total protein. Transudates, being noninflammatory, will have low numbers of cells and less than 3 g/dL protein. This patient's results suggest she has an exudate due to the high number of cells and large amount of protein.

Question 50

Patients with diabetes insipidus tend to produce urine in volume with specific gravity. A. Increased; decreased B. Increased; increased C. Decreased; decreased D. Decreased; increased

Answer 50

A. Diabetes insipidus is caused by a deficiency in antidiuretic hormone. Such deficiencies will result in the kidney's inability to reabsorb water at the distal and collecting tubules. This affects only water reabsorption and not the reabsorption of other urinary solutes. Excreted solute amounts will be the same, but the water volume into which they are excreted will be larger. This results in high urine volumes and low final solute concentrations. The low solute will lead to low specific gravities in these patients' specimens

Question 51

The estimation of hyaluronic acid concentration by measurement of viscosity is useful in evaluating which type of fluid? A. Spinal B. Peritoneal C. Pleural D. Synovial

Answer 51

D. Synovial fluid is a form of plasma ultrafiltrate with added hyaluronic acid. Decreased viscosity and poor mucin clot formation are indications of the decreased hyaluronate concentration of synovial fluid. Either of these findings is usually an indication of inflammation. Because the viscosity of synovial fluid is normally very high, it can be estimated by the length of string formed when the fluid drops from a syringe. The term "mucin" in the mucin clot test is a misnomer, because mucin is not present in synovial fluid.

Question 52

Which of the following is characteristic of an exudate effusion? A. Leukocyte count >1000/uL B. Clear appearance C. Protein concentration <3.0 g/dL D. Absence of fibrinogen

Answer 52

A. Effusions result from an imbalance of the flow of body fluids. Effusions are classified as exudates or transudates on the basis of certain characteristics. Exudates are generally formed in response to inflammation or infection with concomitant capillary wall damage. Exudates are characterized by protein levels greater than 3.0 g/dL, leukocyte counts greater than 1000/uL, and the presence of a sufficient amount of fibrinogen to cause clotting. In contrast, transudates are characterized by protein levels less than 3.0 g/dL, leukocyte counts less than 300/uL, and the absence of fibrinogen. Transudates are generally formed as the result of noninflammatory processes, including alterations in plasma oncotic pressure, pleural capillary hydrostatic pressure, or intrapleural pressure.

Question 53

Which of the following systems utilizes polyelectrolytes to determine the specific gravity of urine? A. Refractometer B. Osmometer C. TS meter D. Reagent strip

Answer 53

D. A clinically useful test for assessing the concentrating and diluting ability of the kidneys is the determination of urine specific gravity. The specific gravity is a measure of the proportion of dissolved solids in a given volume of solvent. Polyelectrolytes are incorporated into urinalysis reagent strips. A dye also present in the strips will change color because of a pKa change in the poly electrolytes. The pKa varies with the ionic concentration of the urine. The color obtained is compared with a set of standard colors, each color correlating with a different specific gravity concentration. The TS meter is a specific type of refractometer that utilizes the close correlation of a solution's refractive index with its solute concentration to determine the specific gravity of urine. The refractive index is the ratio of the velocity of light in air to the velocity of light in a solution, this being comparable to the number of dissolved particles in that solution. An osmometer measures the concentration of dissolved solute in the sample, usually through its relationship to freezing point depression.

Question 54

Which methods may be used to quantify protein in both cerebrospinal fluid and urine specimens? A. Trichloroacetic acid and bromcresol green B. Ponceau S and Coomassie brilliant blue C. Bromcresol green and Coomassie brilliant blue D. Coomassie brilliant blue and trichloroacetic acid

Answer 54

D. Trichloroacetic acid is a turbidimetric method used to quantify small amounts of protein, less than 100 mg/dL, in cerebrospinal fluid (CSF) and urine specimens. Coomassie brilliant blue is a colorimetric dye binding method in which protein complexes with the dye, forming a soluble blue complex. This method also exhibits the necessary sensitivity for detecting small quantities of protein. Bromcresol green is selective for albumin and is used to quantify albumin in serum. Ponceau S is used in serum protein electrophoresis methods to stain both albumin and globulins.

Question 55

Which of the following characteristics is true of the primary urinary components shown in Color Plate 53? A. Consist of uromodulin protein B. Presence always indicates a disease process C. Can be observed with polarized microscopy D. Appear yellowish in brightfield microscopy

Answer 55

A. As seen in Color Plate 53B, hyaline casts are the most commonly observed cast, and they consist completely of uromodulin (Tamm-Horsfall) protein. A reference urine may contain 0-2 hyaline casts per low-power field. Hyaline casts appear translucent using brightfield microscopy because they have a refractive index similar to urine. Phase-contrast microscopy may be used to visualize the casts better.

Question 56

A characteristic of substances normally found dissolved in the urine is that they are all A. Water soluble B. Inorganic C. Organic D. Waste products

Answer 56

A. To be found in urine, a solute must be water soluble. Solutes can be inorganic (e.g., sodium) or organic (e.g., urea). Excreted waste products, meaning end products of metabolism, are creatinine, urea, and uric acid. Some excreted solutes, however, are not present as waste but as overload, such as glucose or sodium.

Question 57

Which of the following statements applies to the proper collection and handling of CSF? A. The second tube collected should be used for chemistry analyses. B. The third tube collected should be used for bacteriologic studies. C. CSF collected in the evening should be refrigerated and assays performed only by day-shift personnel. D. With low-volume specimens, a culture is performed first, before cell counts are done

Answer 57

D. Cerebrospinal fluid (CSF) must be collected in sterile tubes. The first tube is generally used for chemistry and serology studies, the second tube is employed for bacteriologic examination, and the third tube is used for cell counts. Tubes used for chemistry and bacteriologic studies should be centrifuged before use. CSF should remain uncentrifuged for cell counts. Low-volume specimens need to be cultured first (to ensure sterility) before any other test is performed. Because the analysis of CSF should be performed immediately, it is critical that personnel on all shifts be able to perform the necessary testing

Question 58

Which of the following characteristics is true for the urinary components shown in Color Plate 54? A. Never should appear in a freshly collected sample B. Can also resemble cysteine crystals C. Appear insoluble in alkaline urine D. Presence indicates an inborn error of metabolism

Answer 58

B. Uric acid crystals, as seen in Color Plate 54B, are commonly encountered in normal acidic urine but may be observed in neutral urine and rarely in an alkaline urine, because uric acid is soluble at alkaline pH. Using brightfield microscopy, uric acid crystals appear as diamonds, cubes, barrels, rosettes, and may even have six sides and be confused with cysteine. Because they are a reflection of the excretion of purine waste products, they may be pathologically increased in cases of gout and after chemotherapy. They show birefringence (multiple colors) under plane polarized light.

Question 59

A patient sends the following question to an online consumer health Web site: "I am a 22-year-old female who experienced increasing headaches, thirst, and decreasing energy. I was studying in the library when I felt lightheaded and passed out. I was taken to a hospital emergency department and they told me that my serum Acetest® was 40 mg/dL and urine glucose was 500 mg/dL. What does this mean?" How would you reply? A. Your lab results pattern suggests diabetes mellitus. B. You probably have been crash dieting recently. C. The two results do not fit any disease pattern. D. The tests need to be repeated because they could not possibly occur together

Answer 59

A. A positive urine glucose plus a positive serum ketone strongly suggest uncontrolled diabetes mellitus. There is an increased rate of fatty acid oxidation occurring in light of the inaccessibility of the glucose, especially to skeletal muscle. If the patient had only been dieting, the glucose would be negative

Question 60

Which urinalysis reagent strip test will never be reported out as "negative"? A. Protein B. Urobilinogen C. Bilirubin D. Nitrite

Answer 60

B. The sensitivity of a method is the lowest concentration of the analyte that will result in a detectable reaction signal. The protein, bilirubin, and nitrite readout color scales each have a color associated with analyte concentrations less than the method's sensitivity, called "negative." Urobilinogen's readout color scale begins with its lowest reportable value, but there is no pad associated with concentrations less than this.

Question 61

The following urinalysis results were obtained on a 40-year-old white male whose skin appeared yellowish during the clinical examination. Color and clarity— dark brown, clear; protein—negative; glucose—negative; blood—negative; ketones—negative; bilirubin— moderate; urobilinogen—0.2 mg/dL. These results are clinically significant in which of the following conditions? A. Bile duct obstruction B. Cirrhosis C. Hepatitis D. Hemolytic anemia

Answer 61

A. In the hepatic phase of bilirubin metabolism, bilirubin is conjugated with glucuronic acid to form water-soluble conjugated bilirubin. The conjugated bilirubin passes into the bile duct and on to the intestinal tract.

Question 62

Compared to the fecal occult blood test, which of the following is a disadvantage of performing a DNA-based test to detect colon cancer? A. The DNA test is more invasive. B. The DNA test is less sensitive. C. The DNA test is more expensive. D. Additional diet restrictions are needed for the DNA test

Answer 62

C. DNA-based tests for detecting mutations within colon cells are generally more expensive than the fecal occult blood (FOB) methods using the pseudoperoxidase property of hemoglobin. Advantages, however, include no diet or medication restrictions prior to the testing, use of a single stool sample, and a sensitivity (50-73%) that far exceeds that of the FOB test (13-35%) for detecting colon cancer.

Question 63

Which of the following may be associated with morphologic examination of spermatozoa? A. Evaluation should include assessment of 1000 spermatozoa. B. A small number of sperm should have normal morphologic characteristics. C. Papanicolaou stain may be used. D. Presence of red or white cells and epithelial cells need not be noted

Answer 63

C. The morphologic characteristics of spermatozoa are best evaluated by means of smears stained with Papanicolaou stain. Other stains used include Kemechtrot, Giemsa, basic fuchsin, crystal violet, and hematoxylin. When oil immersion is used, a minimum of 200 spermatozoa should be evaluated for morphologic characteristics. Although sources differ as to the exact number, it is generally established that at least 60% of the sperm should have normal morphologic features. When this microscopic analysis is performed, the presence of erythrocytes, leukocytes, epithelial cells, and microorganisms should be indicated.

Question 64

Which condition is characterized by increased levels of immunoglobulins in the cerebrospinal fluid, originating from within the central nervous system and not from the general blood circulation? A. Gout B. Erythroblastosis fetalis C. Multiple myeloma D. Multiple sclerosis

Answer 64

D. Immunoglobulins (IgGs) are normally present at less than 1 mg/dL in the CSF. Increased CSF IgG can result from increased CSF production (e.g., multiple sclerosis) or from increased transport from the blood plasma (compromised blood-brain barrier). Neither gout, erythoblastosis fetalis (isoimmunization syndrome), nor multiple myeloma produces increased CSF IgG levels.

Question 65

Which of the following statements pertains to screening methods used to determine pregnancy? A. Immunoassays will use reagent anti-hCG to react with patient hCG. B. A random urine specimen is the preferred specimen for pregnancy screening tests. C. Internal controls provided within the kit will assess if the patient's specimen was collected correctly. D. External quality control is not needed with these methods

Answer 65

A. Many simplified yet immunologically sophisticated methods exist currently for determining pregnancy. All are based on the reaction between patient human chorionic gonadotropin (hCG) and anti-hCG. Most kits will use an antibody recognizing one subunit of hCG (alpha or beta), whereas other kits may use both anti-a-hCG and anti-p-hCG.

Question 66

The following urinalysis biochemical results were obtained from a 4-month-old infant who experienced vomiting and diarrhea after milk ingestion and failed to gain weight: pH—6; protein—negative; glucose—negative; ketone—negative; bilirubin—negative; Clinitest®—2+. These results are clinically significant in which of the following disorders? A. Diabetes mellitus B. Ketosis C. Starvation D. Galactosemia

Answer 66

D. Galactosemia, an inborn error of metabolism, is characterized by the inability to metabolize galactose, a monosaccharide that is contained in milk as a constituent of the disaccharide lactose. Thus galactose appears in elevated levels in the blood and urine. The condition may result in liver disease, mental retardation, and cataract formation if not treated or controlled. In the biochemical analysis of the urine, the conflicting results for the two glucose tests may be explained as follows: The glucose oxidase reagent strip test is specific for glucose; therefore, the glucose will be negative. The Clinitest®, a modification of the Benedict's test procedure, detects most reducing substances. Because galactose is present in the urine and is a reducing substance, the Clinitest® is positive.

Question 67

Which of the following is a true statement? A. Renal tubular cells originate from the renal pelvis. B. Red blood cells in acid urine (pH 4.5) will usually be crenated because of the acidity. C. Bacteria introduced into a urine specimen at the time of the collection will have no immediate effect on the level of nitrite in the specimen. D. Pilocarpine iontophoresis is the method of choice for the collection of pericardial fluid.

Answer 67

C. Renal tubular cells originate from the renal medulla or cortex. Red blood cell crenation is a phenomenon reflecting increased solute concentration (hyperosmolality) and is not caused by urine pH.