What is a gold standard way of estimating glomerular function in theory, but isn’t used much in practice?
- inulin
- not easy to measure as exogenous
Urea as a measure of glomerular function has what disadvantages?
- levels fluctuate post-parandial
- will underestimate GFR
Urea is a product of _____
- protein metabolism
Creatine is a product of ____
- muscle metabolism
What is a downside of creatinine measurements?
- overestimate GFR
- Creatinine isn’t sensitive to changes in GFR until GFR is low
Define urinary creatine clearance and why it is used?
- more sensitive to changes in GFR at the higher levels
- volume of blood cleared of creatinine per minute by glomerular filtration
How is urinary creatinine clearance calculated?
(urine creatine conc x urine vol) / (serum creatine conc x duration of collection)
The higher the ratio of creatinine clearance =
- more creatine cleared from blood
- better functioning kidneys
Serum creatinine confounders include?
- muscle mass
- diet
- age
- sex
- ethnicitiy
What does eGFR take into consideration?
- potential confounders
GFR should only be reported when the value is _____
- less than 60mL/min
- not good at higher GFR
What can be requested to obtain accurate assessment of higher GFR scores?
- 51Cr- EDTA clerance
Proteinuria > than ____ suggests significant glomerular damage?
- > 150
Causes of large amounts of protein in urine?
- multiple myeloma
- nephrotic syndrome
Describe microalbuminuria?
- excretion of albumin in abnormal quantities but still below the limit of protein detection by dipstick
- early sign of diabetic nephropathy
What measurement is used to assess tubular function?
- serum and urine osmolality
Osmolality means
- how concentrated a solution is
Urine osmolality same as serum osmolality means?
- renal tubules not working well
Urine osmolality different to serum osmolality means?
- tubules working well
