Urinary Chemistry

Question 1

BUN

Answer 1

6-20 mg/dl
Indicates the extent of renal clearance of urea nitrogenous waste product.
An increase BUN does not always mean that renal disease is present.
Factors that elevate BUN are dehydration, hight protein diet, poor renal perfusion, infection.

Question 2

Creatinine

Answer 2

0.2-1.0 mg/dl
End product of protein and muscle metabolism
Reflects GFR.
Increases only when 50% of renal function is lost.
Kidney disease is the only condition that increases creatinine.

Question 3

GFR (glomerular filtration rate)

Answer 3

125ml/min

Question 4

Urine specific gravity

Answer 4

1.002-1.030
Urine concentration
A high specific gravity = high concentration of solutes in urine (dehydration)
Low specific gravity = low concentration of solutes