My age 76. Have been told I’m ready for dialysis. Tests don’t show the GFR rate. How to calculate it? I see an equation where numbers can be plugged in on your site, but it asks for something called Serum Cystatin with a range of 0.82-1.52 mg/l for a person my age and I don’t know which of these two pages full of tests would be the correct one. I am able to answer all the other questions. Is the Cystatin known by any other name? Thanks so much for your help.

Cystatin C is used in some experimental circumstances and by the insurance industry to estimate kidney function, but the serum creatinine is used in most clinical situations.  The serum creatinine and your other demographic information can be used to calculate your estimated glomerular filtration rate (eGFR).  You can find this equation on our web site at:

In this equation, it is not necessary to enter the Cystatin C to get an eGFR.

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