Biochemical measurements

Question 1

1. Urea is the endpoint of _______ metabolism. This occurs in the liver. 75% is excreted by the kidneys while 25% returns to the ____.
2. __________ is released from muscle metabolism.

Answer 1

Protein (purine)
Gut
Creatinine

Question 2

1. What is the urinary creatinine clearance?
2. How is it measured?
3. How is it calculated?

Answer 2

1. The volume of blood that is cleared of creatinine per minute by glomerular filtration
2. Creatinine is measured in the serum and in a 24 hour urine collection and the volume of urine is also measured
3. [Urine creatinine conc. x urine volume] divided by [serum creatinine conc. x duration of collection]

Question 3

1. What variables effect serum creatinine levels?

Answer 3

1. diet, muscle mass, therefore age/ethnicity/sex