Urinalysis Ch. 5

Case 5-1 5. Calculate the urine albumin-to-creatinine ratio in micrograms albumin per milligram of creatinine (μg albumin/mg creatinine).

50 μg/mg creatinine

Case 5-1 4. Calculate the albumin excretion in micrograms per minute (μg/ min).

66 μg/min

Case 5-1 3. Calculate the albumin excretion in milligrams per day (mg/day).

95 mg/day

1. Which of the following solutes are present in the largest molar amounts in urine? A. Urea, chloride, and sodium B. Urea, creatinine, and sodium C. Creatinine, uric acid, and ammonium D. Urea, uric acid, and ammonium

A Urea, chloride, and sodium

30. The following data are obtained from a 60-year-old female who is 4′8 ̋ tall and weighs 88 lb: Plasma creatinine: 1.2 mg/dL Urine creatinine: 500 mg/L Urine volume: 1440 mL/24 hr A. Calculate the creatinine clearance. B. Calculate the normalized creatinine clearance. (Determine the body surface area using Equation 5-6 [logSA =(0.425×logW)+(0.725×logH)−2.144].) C. Are these results normal for this patient? (Use reference intervals provided in Table 5-3.)

A. 42 mL/min (Note that the plasma and urine creatinine results must first be converted to the same units.) B. 58 mL/min C. Yes

19. Which renal function is assessed using specific gravity and osmolality measurements? A. Concentrating ability B. Glomerular filtration ability C. Tubular excretion ability D. Tubular secretion ability

A. Concentrating ability

3. The concentration of which substances provides the best means of distinguishing urine from other body fluids? A. Creatinine and urea B. Glucose and protein C. Uric acid and ammonia D. Water and electrolytes

A. Creatinine and urea

24. Calculate the osmolar and free-water clearances using the following patient data. Serum osmolality: 305 mOsm/kg Urine osmolality: 250 mOsm/kg Urine volume: 300 mL/2 hours A. Is this individual excreting more water than is necessary for solute removal? Yes/No B. Is the osmolar clearance "normal" (i.e., 2.0 to 3.0 mL/min)? Yes/No C. From the free-water clearance result obtained, is the urine hypo-osmotic or hyperosmotic?

A. Yes B. Yes C. Hypo-osmotic

18. All of the following conditions may produce nocturia except A. anuria. B. pregnancy. C. chronic renal disease. D. fluid intake at night.

A. anuria.

31. A 24-hour urine collection is preferred for determination of creatinine clearance because of diurnal variation in the A. glomerular filtration rate. B. plasma creatinine. C. creatinine excretion. D. urine excretion.

A. glomerular filtration rate.

Case 5-2 2. Without fluid restrictions, this patient's urine osmolality most likely is A. less than 200 mOsm/kg. B. greater than 200 mOsm/kg.

A. less than 200 mOsm/kg.

8. Another name for excessive thirst is A. polydipsia. B. polyuria. C. hydrophilia. D. hydrostasis.

A. polydipsia.

34. The glomerular filtration rate is controlled by A. the renal blood flow. B. the renal plasma flow. C. the countercurrent mechanism. D. hormones (e.g., aldosterone, antidiuretic hormone).

A. the renal blood flow.

37. Measuring the quantity of hydrogen ion excreted as titratable acids and ammonium salts in urine provides a measure of A. tubular secretory function. B. tubular reabsorptive function. C. glomerular filtration ability. D. renal concentrating ability.

A. tubular secretory function.

17. The ultrafiltrate in the urinary space of the glomerulus has a specific gravity of A. 1.005 and a lower osmolality than the blood plasma. B. 1.010 and the same osmolality as the blood plasma. C. 1.015 and a higher osmolality than the blood plasma. D. 1.035 and a higher osmolality than the blood plasma.

B. 1.010 and the same osmolality as the blood plasma.

33. A 45-year-old female African American had her serum creatinine determined using a creatinine method that is NOT calibrated to an IDMS reference method. Her serum creatinine was 1.5 mg/dL; what is her eGFR using the appropriate MDRD equation? A. 40 mL/min/1.73 m2 B. 48 mL/min/1.73 m2 C. 51 mL/min/1.73 m2 D. 54 mL/min/1.73 m2

B. 48 mL/min/1.73 m2

32. Which of the following situations results in an erroneous creatinine clearance measurement? A. A 24-hour urine collection from an individual on a vegetarian diet B. A 24-hour urine collection maintained at room temperature throughout the collection C. A plasma sample drawn at the beginning instead of during the 24-hour urine collection D. Creatinine determinations made using the non-specific alkaline picrate method (Jaffe reaction)

B. A 24-hour urine collection maintained at room temperature throughout the collection

Case 5-2 5. Which of the following tests should be used to evaluate this patient? A. Free-water clearance test B. Fluid deprivation test C. Glucose tolerance test D. Osmolar clearance test

B. Fluid deprivation test

23. A free-water clearance value of −1.2 would be expected from a patient experiencing A. polyuria. B. dehydration. C. water diuresis. D. excessive fluid intake.

B. dehydration.

15. When the body is dehydrated, the kidneys A. excrete excess solutes in a constant volume of urine. B. excrete solutes in as small a volume of urine as possible. C. decrease the quantity of solutes excreted and decrease the urine volume. D. increase the quantity of solutes excreted while holding the urine volume constant.

B. excrete solutes in as small a volume of urine as possible.

22. The volume of plasma cleared per minute in excess of that required for solute elimination is called the A. creatinine clearance. B. free-water clearance. C. osmolar clearance. D. renal clearance.

B. free-water clearance.

2. Renal excretion is not involved in the elimination of A. electrolytes and water. B. normal by-products of fat metabolism. C. soluble metabolic wastes (e.g., urea, creatinine). D. exogenous substances (e.g., drugs, x-ray contrast media).

B. normal by-products of fat metabolism.

21. A fluid deprivation test involves the measurement of serum and urine A. density. B. osmolality. C. specific gravity. D. volume.

B. osmolality.

26. Renal clearance is defined as the volume of A. urine cleared of a substance per minute. B. plasma cleared of a substance in a time interval. C. plasma flowing through the kidney per minute. D. plasma containing the same amount of substance in 1 mL of urine.

B. plasma cleared of a substance in a time interval.

9. Specific gravity measurements are not affected by A. temperature. B. solute charge. C. solute mass. D. solute number.

B. solute charge.

Case 5-2 1. Explain briefly the cause of polyuria in patients with diabetes insipidus.

Because of damage to the hypothalamus or the posterior pituitary, antidiuretic hormone production is partially or totally deficient. Consequently, tubular reabsorption of water does not occur and polyuria results.

5. The osmolality of a solution containing 1.0 mole of urea is equal to that of a solution containing A. 1.0 mole of HCl. B. 1.0 mole of H2PO4. C. 0.5 mole of NaCl. D. 0.5 mole of glucose.

C. 0.5 mole of NaCl.

36. What percentage of the total cardiac output is received by the kidneys? A. 8% B. 15% C. 25% D. 33%

C. 25%

14. The daily volume of urine excreted normally ranges from A. 100 to 500 mL/day. B. 100 to 1800 mL/day. C. 500 to 1800 mL/day. D. 1000 to 3000 mL/day.

C. 500 to 1800 mL/day.

25. Which of the following is an endogenous substance used to measure glomerular filtration rate? A. Urea B. Inulin C. Creatinine D. p-Aminohippurate

C. Creatinine

12. Occasionally the specific gravity of a urine specimen exceeds that physiologically possible (i.e., >1.040). Which of the following substances when found in urine could account for such a high value? A. Creatinine B. Glucose C. Mannitol D. Protein

C. Mannitol

4. What is the definition of the osmolality of a solution? A. The density of solute particles per liter of solvent B. The mass of solute particles per kilogram of solvent C. The number of solute particles per kilogram of solvent D. The weight of solute particles per liter of solvent

C. The number of solute particles per kilogram of solvent

20. A fluid deprivation test is used to A. determine renal plasma flow. B. investigate the cause of oliguria. C. assess renal concentrating ability. D. measure the glomerular filtration rate.

C. assess renal concentrating ability.

Case 5-2 4. In patients with neurogenic diabetes insipidus, if antidiuretic hormone is given intravenously, the urine osmolality should A. remain unchanged. B. decrease. C. increase.

C. increase.

35. For measurement of renal plasma flow, p-aminohippurate is an ideal substance to use because it A. is easily measured in urine and plasma. B. is endogenous and does not require an infusion. C. is secreted completely in its first pass through the kidneys. D. maintains a constant plasma concentration throughout the test.

C. is secreted completely in its first pass through the kidneys.

10. Osmolality is a measure of solute A. density. B. mass. C. number. D. weight.

C. number.

7. Serum osmolality remains relatively constant, whereas the urine osmolality ranges from A. one-third to one-half that of serum. B. one-third to equal that of serum. C. one to three times that of serum. D. three to five times that of serum.

C. one to three times that of serum.

6. The maximum osmolality that urine can achieve is determined by the A. quantity of solutes ingested in the diet. B. presence of antidiuretic hormone in the collecting tubules. C. osmolality of the medullary interstitium. D. osmolality of fluid entering the collecting tubules.

C. osmolality of the medullary interstitium.

11. Which of the following solutes, if added to pure water, affects the specific gravity more than it affects its osmolality? A. Sodium B. Chloride C. Potassium D. Glucose

D. Glucose

28. Which of the following groups would be expected to have the greatest 24-hour excretion of creatinine? A. Infants B. Children C. Women D. Men

D. Men

38. The oral ammonium chloride test evaluates the ability of the tubules to secrete A. ammonium and chloride. B. phosphate and sodium. C. bicarbonate and chloride. D. ammonia and hydrogen.

D. ammonia and hydrogen.

27. Creatinine is a good substance to use for a renal clearance test because it A. is exogenous. B. is reabsorbed. C. is affected by fluid intake. D. has a constant plasma concentration.

D. has a constant plasma concentration.

29. Creatinine clearance results are "normalized" using an individual's body surface area to account for variations in the individual's A. age. B. sex. C. dietary intake. D. muscle mass.

D. muscle mass.

16. The excretion of less than 400 mL of urine per day is called A. anuria. B. hypouria. C. nocturia. D. oliguria.

D. oliguria.

13. The excretion of large volumes of urine (>3 L/day) is called A. glucosuria. B. hyperuria. C. polydipsia. D. polyuria.

D. polyuria.

Case 5-2 3. This patient's polyuria should be classified as A. oncotic diuresis. B. psychosomatic diuresis. C. solute diuresis. D. water diuresis.

D. water diuresis.

Case 5-2 Indicate whether each of the following statements is true (T) or false (F). 6. Patients with diabetes insipidus often have glucose present in the urine.

F

Case 5-2 Indicate whether each of the following statements is true (T) or false (F). 7. Patients with diabetes insipidus often have a high urine specific gravity.

F

Case 5-2 Indicate whether each of the following statements is true (T) or false (F). 8. Patients with diabetes insipidus often have urinary ketones present because of an inability to use the glucose present in the blood.

F

Case 5-1 2. Calculate the normalized creatinine clearance result using the data provided.

Normalized creatinine clearance: 55 (54.7) mL/min (using Equation 5-5 [C (mL/min) = U×V 1.73m2 P × SA])

Case 5-1 1. Calculate this patient's body surface area using Equation 5-6 (logSA =(0.425×logW)+(0.725×logH)−2.144).

Surface area: 1.80

Case 5-2 Indicate whether each of the following statements is true (T) or false (F). 9. Diabetes is a general term referring to disorders characterized by copious production and excretion of urine.

T