24 hour Clearance vs. eGFR

[Desert Dancer]

Hello, all -

I recently did a 24 hour creatinine clearance - the first I've done in a long time. My understanding of creatinine clearance has been that it is a rough estimate of remaining percentage of function: more accurate than clearance via the old Cockcroft-Gault formula, but still only an estimate. I've also been given to understand that eGFR is more accurate than both.

Now, here's my question: when I began dialysis on 8.22 I had an eGFR of 8. When I did my 24 hour clearance on 9.1 I had a creatinine clearance of 2.7. If I'm reading this correctly, my remaining kidney function was wiped out in about a week-and-a-half of dialysis.

Can this be right? Am I looking at these numbers correctly and if so, are they two numbers that can be compared to one another?

[Restorer]

A lot of it has to do with the water weight you're holding onto. I was on PD for over a year and a half. When it was working great, I was hardly peeing - maybe once a day. Then I had peritonitis, and I stopped ultrafiltrating. I put on over 20 pounds of water weight. At that point, I was back to peeing 800+ ml a day. Now that I'm on hemo, I'm back down to just once or twice a day. My last 24-hour collection measure only 150 ml.

As long as your kidneys haven't completely shut down, they'll still respond to water retention and sodium intake, and they can still help out when you really need it. When they're motivated to process more water, bits of waste will go with it.

Unfortunately, as long as you're on hemo and not building up fluid, you won't be putting out as much water, and so not as much waste.

[Desert Dancer]

Hi, Matt -

That makes sense but brings up another question: they aren't pulling any fluid off me, except what comes off incidentally when they maintain me, generally 1 to 2 kilos. I don't usually put on any more than .5 kilos between treatments.  When I did my 24 hour I collected 1400mL, not nearly as much as even a month ago but still significant, and I've never had edema. Obviously I'm retaining some fluid but not much.

How does this affect your explanation, if at all? Thank you, by the way, for your first answer.