Biochemical measurements in renal disease

Question 1

what factors are considered to calculate eGFR?

Answer 1

Creatinine,

Age,

Sex,

Race

Question 2

When does eGFR become inaccurate?

Answer 2

at GFRs over 60 ml/min

Question 3

what substance do you use to get an accurate measurement of GFR?

Answer 3

51Cr-EDTA

Question 4

what level of protein in the urine would suggest significant glomerular damage?

Answer 4

Protein >150mg/day

Question 5

What is nephrotic syndrome?

Answer 5

Nephrotic syndrome is a nonspecific kidney disorder characterized by a number of signs of disease: proteinuria, hypoalbuminemia and oedema

Question 6

Define Microalbuminuria

Answer 6

• Refers to excretion of albumin in abnormal quantities but still below the limit of protein detection by dipstick
• Is earliest expression of diabetic nephropathy

Question 7

what are the different ways of expressing proteinuria?

what levelsof all these measurements would suggest nephrotic syndrome?

Answer 7

dipstick reading,

protein creatinine ratio,

total protein,

albumin creatinine ratio,

Question 8

What levels would Urine sodium, Urine/serum urea & Urine/serum osmolality be at in pre-renal failure/ intrinsic renal damge

Answer 8

pre-renal failure is caused by hypovolaemia and the tubules are still working. Fluid is retained through increased Na+ reabsorption therefor Na+ in urine is low. Urine osmolality and urea concentraion is high beacuse the urine is concentrated.

Na+ <20 mmol/L

Urine/ Serum urea >10:1

Urine/ Serum Osmolality >1.5:1

The tubules do not work in intrinsic renal damage. Na+ is not reabsorbed well and urine osmolarity and urea is closer to plasma levels.

Na+ >40 mmol/L

Urine/ Serum Urea <3:1

Urine Osmolality <1.1:1