PATHOLOGY OF BODY FLUIDS
CHAPTER #5 EXAM GUIDE QUESTIONS
AND ANSWERS
Differentiate between glomerular and tubular proteinuria. - Answer-Glomerular
proteinuria occurs when protein (primarily albumin) passes through the glomerulus,
whereas tubular proteinuria represents defects in the tubular reabsorption of low
molecular weight proteins usually filtered and reabsorbed.
How does detection of microalbuminuria affect patient treatment? - Answer-The patient
requires better stabilization of blood glucose levels.
Briefly explain the principle of the protein error of indicators. How does a highly alkaline
urine affect this? - Answer-When the pH remains constant, certain indicators change
color in the presence of protein; highly alkaline urine will override the reagent strip pH
buffer, thus producing a color change related to pH, not protein.
State a pathologic reason that would cause a negative reagent strip protein reaction and
a
positive SSA test result. - Answer-Multiple Myeloma
Explain why glycosuria occurs in the presence of hyperglycemia. - Answer-Blood
glucose levels greater than the renal threshold for glucose produce glucose
concentrations in the filtrate that exceed the maximum reabsorptive capacity of the
tubules.
Explain why the following people would exhibit hyperglycemia and glucosuria:
a. A person with hyperthyroidism - Answer-The hormone thyroxine opposes the action
of insulin by breaking down glycogen to glucose.
Explain why the following people would exhibit hyperglycemia and glucosuria:
b. A person under extreme stress. - Answer-Epinephrine inhibits insulin secretion
How can glycosuria occur in the absence of hyperglycemia? - Answer-Renal tubular
dysfunction
Explain the purpose of glucose oxidase and peroxidase in the reagent strip test for
glucose. - Answer-Glucose oxidase catalyzes a reaction between glucose and room air
to form hydrogen peroxide, which is then broken down by peroxidase to produce
oxygen that oxidizes a chromogen, producing a color.
What is the primary cause of a false-negative test result for glucosuria? - Answer-Old
specimens; glycolysis
, Does the Clinitest detect oxidizing or reducing substances? How does it do this? -
Answer-Reducing substances that reduce cupric ions to cuprous ions, releasing oxygen
to produce an oxidized colored substance.
How will failure to detect "pass through" affect results - Answer-A strongly positive result
will be reported as negative.
What is the primary reason that laboratories perform the Clinitest? - Answer-Screening
for galactosuria in children.
State two reasons for a positive reagent strip test result for glucose and a negative
Clinitest
result. - Answer-Reagent strip tests are more sensitive than clinitest;
contamination of containers by strong oxidizing agents.
State the three basic reasons for the presence of ketonuria. - Answer-Inadequate
metabolism or intake of carbohydrates and increased loss of carbohydrate.
What is the primary substance detected by sodium nitroprusside? Why is glycine added
to the
reaction? - Answer-Acetoacetic acid; glycine enhances the detection of acetone.
How do the reactions between ketones and interfering substances differ on reagent
strips? - Answer-Reaction color from interfering substances fades after standing,
whereas color from ketones inceases.
Name three pathologic substances detected by the reagent strip blood reaction. State a
reason
why each of these appears in the urine. Substance Reason - Answer-a. _RBC's:
glomerular damage, trauma
b.__Hemoglobin: intravascular hemolysis.
c.__Myoglobin: muscle destruction.
Why is hemoglobinuria associated with pink plasma and myoglobinuria with normal-
colored
plasma? - Answer-Myoglobin is more rapidly cleared from the plasma.
Why might yellow-brown granules appear in the urine sediment? - Answer-Denaturation
of hemoglobin to ferritin by the renal tubular epithelial cells, producing hemosiderin
granules.
Following precipitation of a clear, red urine with ammonium sulfate, what is the
significance
of a red supernatant? - Answer-Myoglobin is present.
CHAPTER #5 EXAM GUIDE QUESTIONS
AND ANSWERS
Differentiate between glomerular and tubular proteinuria. - Answer-Glomerular
proteinuria occurs when protein (primarily albumin) passes through the glomerulus,
whereas tubular proteinuria represents defects in the tubular reabsorption of low
molecular weight proteins usually filtered and reabsorbed.
How does detection of microalbuminuria affect patient treatment? - Answer-The patient
requires better stabilization of blood glucose levels.
Briefly explain the principle of the protein error of indicators. How does a highly alkaline
urine affect this? - Answer-When the pH remains constant, certain indicators change
color in the presence of protein; highly alkaline urine will override the reagent strip pH
buffer, thus producing a color change related to pH, not protein.
State a pathologic reason that would cause a negative reagent strip protein reaction and
a
positive SSA test result. - Answer-Multiple Myeloma
Explain why glycosuria occurs in the presence of hyperglycemia. - Answer-Blood
glucose levels greater than the renal threshold for glucose produce glucose
concentrations in the filtrate that exceed the maximum reabsorptive capacity of the
tubules.
Explain why the following people would exhibit hyperglycemia and glucosuria:
a. A person with hyperthyroidism - Answer-The hormone thyroxine opposes the action
of insulin by breaking down glycogen to glucose.
Explain why the following people would exhibit hyperglycemia and glucosuria:
b. A person under extreme stress. - Answer-Epinephrine inhibits insulin secretion
How can glycosuria occur in the absence of hyperglycemia? - Answer-Renal tubular
dysfunction
Explain the purpose of glucose oxidase and peroxidase in the reagent strip test for
glucose. - Answer-Glucose oxidase catalyzes a reaction between glucose and room air
to form hydrogen peroxide, which is then broken down by peroxidase to produce
oxygen that oxidizes a chromogen, producing a color.
What is the primary cause of a false-negative test result for glucosuria? - Answer-Old
specimens; glycolysis
, Does the Clinitest detect oxidizing or reducing substances? How does it do this? -
Answer-Reducing substances that reduce cupric ions to cuprous ions, releasing oxygen
to produce an oxidized colored substance.
How will failure to detect "pass through" affect results - Answer-A strongly positive result
will be reported as negative.
What is the primary reason that laboratories perform the Clinitest? - Answer-Screening
for galactosuria in children.
State two reasons for a positive reagent strip test result for glucose and a negative
Clinitest
result. - Answer-Reagent strip tests are more sensitive than clinitest;
contamination of containers by strong oxidizing agents.
State the three basic reasons for the presence of ketonuria. - Answer-Inadequate
metabolism or intake of carbohydrates and increased loss of carbohydrate.
What is the primary substance detected by sodium nitroprusside? Why is glycine added
to the
reaction? - Answer-Acetoacetic acid; glycine enhances the detection of acetone.
How do the reactions between ketones and interfering substances differ on reagent
strips? - Answer-Reaction color from interfering substances fades after standing,
whereas color from ketones inceases.
Name three pathologic substances detected by the reagent strip blood reaction. State a
reason
why each of these appears in the urine. Substance Reason - Answer-a. _RBC's:
glomerular damage, trauma
b.__Hemoglobin: intravascular hemolysis.
c.__Myoglobin: muscle destruction.
Why is hemoglobinuria associated with pink plasma and myoglobinuria with normal-
colored
plasma? - Answer-Myoglobin is more rapidly cleared from the plasma.
Why might yellow-brown granules appear in the urine sediment? - Answer-Denaturation
of hemoglobin to ferritin by the renal tubular epithelial cells, producing hemosiderin
granules.
Following precipitation of a clear, red urine with ammonium sulfate, what is the
significance
of a red supernatant? - Answer-Myoglobin is present.
