Biochemical Measurements Flashcards
What takes place in PCT?
reabsorption
What takes place in loop of Henle?
concentration of the medulla
What takes placei n the DCT?
secretion and reabsorption (fine-tuning)
What takes place in the collecting duct?
water reabsorption
What is the gold standard for measuring GFR?
inulin
What are the problems iwth inulin?
exogenous and not easy to measure
What organ produces urea from ammonia?
liver
How much creatinine is secreted by the distal tubule?
5-10%
What is the problem with creatinine??
above 60ml/min there is little change in creatinine despite steep fall in GFR
What are the confounders for serum creatinine?
age; sex; muscle mass and diet
What is clearance?
the volume of plasma cleared of a substance perminute
What is equation for the clearance of a substance?
conc. of X in urine x Vu/ plasma conc. of X
Whati s the Cock-croft-Gault method used for?
used to calculate drug dosages
What type of clearnace of creatinine is most sensitive?
urine creatinine is better than serum creatinine
What amount of protein per day indicates significant glomerular damage?
> 150mg/day
Why is protein/creatinine ratio spot sample better than just measuring protein?
urine may be dilute or concentration so comparing to creatinine adjusts for that
What is a normal PCR?
<15mg/mmol
Whati s the earliset expression of diabetic nephropathy?
microalbuminuria
What does microalbuminuria refer to?
excretion of albumin in abnormal quantities but isn’t picked up by dipstick
What drug is given to treat microalbuminuria?
ACEi
What gives an indication of how the tubules are working?
urine/serum osmolality
What does a urine/serum osmolality of 1 indicate?
that the tubules aren’t working as there has been no reabsorption of water and so there must be intrisnic renal damage
What are the two main causes of proteinuria?
overflow- too much protein and glomerular- where the glomerulus is leaky
What is the commonest cause of proteinuria?
glomerular
What is an example of overflow proteinuria?
multiple myeloma
