Clinical Chemistry II- BUN/Uric Acid Questions With Complete Solutions

The liver converts ammonia (from the breakdown of amino acids) into _________ which is excreted by the kidneys. correct answer: Urea Urea nitrogen makes up about _____ of the total NPN in the blood. correct answer: 45% Urea is _______ filtered by the kidneys, but approximately half of the filtered urea is normally _______ by the tubules. correct answer: freely, absorbed T or F: BUN can be used alone to determine kidney function. correct answer: F. It is a useful index for such diagnosis but cannot be used alone as other factors can affect BUN levels. An increase in BUN is known as __________ correct answer: Azotemia/Uremia Increase in NPN may be due to what three categories of causes? correct answer: -Pre-renal (before kidney) -Renal (Kidney) -Post-renal (after kidney) These factors that increase BUN levels may be water depletion, increased protein breakdown, high protein diet, inadequate blood flow to the kidneys, reduced filtration, and heart failure correct answer: Pre-renal These factors that increase BUN levels are usually due to reduced glomerular filtration due to acute or chronic renal disease correct answer: Renal These factors that increase BUN levels include all types of urinary tract obstruction such as renal stones, tumors, or an enlarged prostate. correct answer: Post-renal T or F: Urine urea nitrogen levels are commonly evaluated. correct answer: F. They are rarely done except as part of the urea clearance test. T or F: Decreased BUN concentrations are commonly seen. correct answer: F. They are not frequently seen but may occur due to decrease synthesis or reabosorption because of diet, liver disease, or excess hydration and secretion.