warning, KIDNEY DISEASE usually causes cardiac disease so this may well be a case of which came first, the chicken or the Egg!!!!!
I am 53 egfr, and have been referred. some do wait till under 40 but studies show early referal has better outcomes. i have only been refered early as the decline is so extremely rapid over 3 tests. I have no bladder so CKD is not a surprise. i am 50 years old and didnt expect this for a number of years but ah well!!!!!! I wouldnt suggest wating till under 30, if ESKD will need a fistula made for dialysis and this takes 6 months to mature before it can be used. i had my fistula put in recently.
glom filt rate= glomerular filtration rate or GFR.
here is a good website explaining what GFR is: http://www.kidney.org/kidneydisease/ckd/knowGFR.cfm
Your mother is at stage 3 out of 5:
3 Moderate decrease in GFR 30 to 59
just make sure she sees a nephrologist (a kidney doctor) to keep track of her kidney's. her GFR is most likely decreased due to her "end stage heart disease"
to save you time: Glomerular Filtration Rate (GFR): Your GFR tells how much kidney function you have. It may be estimated from your blood level of creatinine. If your GFR falls below 30 you will need to see a kidney disease specialist (called a nephrologist), Your kidney doctor will speak to you about treatments for kidney failure like dialysis or kidney transplant. A GFR below 15 indicates that you need to start one of these treatments.