Nonprotein nitrogen compounds - Ch. 12

Serum urea levels are less affected by diet and metabolism than are serum creatinine levels. True False

False

BUN-to-Creatinine ratio is computed as BUN/Creatinine? True False

True

Creatinine clearance is calculated from the following formula urine creatinine (mg/dL) × urine mL per 24hr/1,440 plasma creatinine (mg/dL) × (1.73/ body surface area) The normal range is listed below which decreases in renal disease and serves as an early indicator M: 97-137 mL/min F: 88-128 mL/min True False

True

Indirect urea methods begin with the hydrolysis of urea to ammonia. True False

True

A patient sample for uric acid gave an absorbance reading of 0.4; the 50 mg/dL standard used in the test gave an absorbance reading of 0.1. What is the concentration of uric acid in the patient's sample in grams per deciliter? a. 0.2 b. 12.5 c. 125 d. 200

a. 0.2

Given the following lab results, what is the most likely cause of this patient's BUN? BUN45 mg/dL Creatinine1.8 mg/dL Uric Acid7 mg/dL pH7.22 pCO274.4 mm Hg pO232.8 mm Hg O2 sat.51.3% a. Congestive heart failure b. Chronic renal disease c. Dialysis d. Acute tubular necrosis

a. Congestive heart failure

The most widely used method for bilirubin analysis uses two reagents, ____________ and ___________, in the diazo reaction. a. Sulfanilic acid; sodium nitrite b. Glucuronic acid; sodium nitrate c. Glucuronic acid; sodium nitrite d. Sulfanilic acid; sodium nitrate

a. Sulfanilic acid; sodium nitrite

Urea can be measured in all of the following ways EXCEPT: a. The Caraway method b. Ammonium ions generated by the urease reaction leading to a detectable pH change c. Electrode to measure the rate of increase in conductivity as ammonium ions d. Isotope-dilution mass spectrometry

a. The Caraway method

How many milliliters of concentrated sulfuric acid (H2S04), M.W. = 98 grams, specific gravity = 1.500, purity = 80%, are needed to make 400 mL of a 2N solution? a. 26.1 b. 32.7 c. 52.3 d. 65.3

b. 32.7

Which of the following best describes the correct collection and handling conditions for a blood ammonia measurement? a. Fasting patient, draw clot tube, separate serum immediately, test immediately b. Draw sodium heparin tube, place in ice bath immediately, separate cells and plasma in refrigerated centrifuge, immediately remove plasma and freeze if analytical testing is delayed c. Draw clot tube, separate serum from clot in refrigerated centrifuge, protect from light, freeze if not tested immediately d. Fasting patient, draw lithium heparin tube, place tube on an ice pack, centrifuge at 20° C, test immediately

b. Draw sodium heparin tube, place in ice bath immediately, separate cells and plasma in refrigerated centrifuge, immediately remove plasma and freeze if analytical testing is delayed

When a purified enzyme is used as a reagent, such as urease in the measurement of urea, the enzyme must be ________________ concentration so that the reaction follows _________________ kinetics. a. Limited; first b. Excess; first c. Limited; zero d. Excess; zero

b. Excess; first

A toxic condition involving a very high serum level of urea and creatinine accompanied by failure of the three main functions of the renal system is referred to as: a. Acute glomerulonephritis b. Uremia c. Azotemia. d. Acute renal failure

b. Uremia

A creatinine clearance is done on a patient with the following results: serum creatinine, 0.6 mg/dL; urine creatinine, 102 mg/dL; urine volume, 1650 mL/24 hours; body surface area, 1.93 m2. This patient's creatinine clearance, corrected for body surface area, is: a. 93 mL/min b. 130 mg/dL c. 175 mL/min d. 195 mL/min e. 217 mL/min

c. 175 mL/min

The major causes of decreased plasma urea concentration include: a. Congestive heart failure b. Glomerular nephritis c. Low protein intake and sever liver disease d. Tubular necrosis e. Obstruction of urine flow by renal calculi

c. Low protein intake and sever liver disease