glomerular filtration rate
ability of the kidneys to clear out waste products
what is a normal GFR per day?
150-250 L/24 hrs
why do we measure kidney function with creatinine?
it is always being sloughed off from muscles
low level of creatinine in urine means
low kidney function
what are the three ways to estimate GFR?
- Cockcroft-Gault formula
- MDRD (modification of diet in renal dz)-best estimate
- 24 hr urine
what does MDRD help to differentiate?
race and gender and age
- AA progress slower
- males have higher protein
what does Cockcroft-Gault help to differentiate?
male/female and age
how is ESRD defined?
on dialysis or GFR of <15%
what is the formula for Cockcroft-Gault?
[(140-age) x wt (kg)] / (Plasma Cr x 72)
what do you multiple Cockcroft-Gault times to adjust for female?
0.85
what is a restriction of Cockcroft-Gault?
overestimates GFR in obese and edemous patients
what has to happen when pt turns in a 24 hour urine specimen
get serum Cr!!!!!!!!!!!
what is the Cr clearance equation?
(UCr x Uv) / (SCr x time (1440 minutes))
what is an acceptable proteinuria value?
< 150mg/24hrs
what is acceptable proteinuria value for DM pts?
<30mg/ 24hr
what is the nephrotic range of proteinuria?
> 3.5 g / 24 hrs
which spot test will you order with high risk pt with negative dipstick?
albumin-creatinine ratio
normal is < 30
which spot test will you order with positive dipstick?
protein-creatinine ratio
