Cystatin C egfr - affected by exercising?


New Member
My creatinine usually gets really high for the days following exercise to the point my traditional EGFR goes from high 70s down to even 40s if I do it the days after an intense back or leg workout because of the creatinine elevation

I just ordered cystatin C since that apparently isn't affected by muscle mass (I'm 240, 19" arms much more muscle than a "normal" person and work out very intensely 4 x a week), is it safe to take the test without cutting back on my work outs?

Also is it affected by what you eat? One time I took a regular egfr test a couple of hours after hitting a Brazilian BBQ and eating several pounds of steak, the results were.. interesting. Luckily my old dr was fine with it.

Nelson Vergel

Hi Bubbs

Cystatin C is not affected by body weight, creatine supplements, exercise or diet.



New Member
Thank you Nelson! I hope the test results are good, the roller coaster numbers from traditional creatinine testing has got me a little concerned


New Member
I'll post here as soon as I get the result

for context,

Xmas 2018 eGFR If Africn Am - 48 (worked out 1 day before, ate, dehydrated)

June 2019 eGFR If Africn Am - 84 (no exercise for a week pre test, fasted)

Xmas 2019 - 55 (ate a ton of meat before the test)

June 2020 - 68 (no exercise for 3 days prior, ate cheeseburger that morning)

My other numbers are all fine but this and BUN to a degree seem to go up and down depending on my routine so it's really hard to see if I'm ok or not lol

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