Cystatin-C vs Creatinine eGFR

[g.r.o.w.t.h.]

Recent bloodwork:

Creatinine 1.3 eGFR 70
Cystatin-C 0.72 eGFR 118

Fairly drastic difference. Opinions on which one is more accurate?

 

[qbkilla]

I'm no expert but I think cystian c as creatine can be affected by variables such as hydration, training close to the test, etc

 

[plane]

Cystatin C is generally a better indictiator but I would get a 24 hour creatinine clearance test and add that to your diagnostics to get a better picture. Either way, you're absolutely fine with both numbers - I wouldn't be concerned at all (granted that you're a big dude with alot of muscle mass and low bodyfat eating a high protein diet)

 

[g.r.o.w.t.h.]

I'm no expert but I think cystian c as creatine can be affected by variables such as hydration, training close to the test, etc

All true, these numbers came from the same blood draw.

 

[Flex500]

Recent bloodwork:

Creatinine 1.3 eGFR 70
Cystatin-C 0.72 eGFR 118

Fairly drastic difference. Opinions on which one is more accurate?

You just have to remember that eGFR is just a calculation. Cystatin C is a great and accurate indicator of kidney function on it's own and creatinine is a decent marker used as trends over time...not a one time snapshot. Meaning, my creatinine as been "high" for 22 years. It's been 1.25 to 1.45 over that time oscillating a little one way or the either with my lowest numbers the last couple years. Another way to think of it is you could have an old women with a creatinine of 1.0 and that sounds great...unless you see the trends that it was 0.56 a year ago and it ticks up and up every month. Anyway, you get my point, creatinine is great for trends over time (years) and I wouldn't get caught up in how it impacts your eGFR calculation. Also there are many calculations that take into account muscle mass but they are not used as a standard.

I also at the creatinine:microalbumin ration urine test and a standard urine test. The standard urine will only test for larger protein particles and if you are over hydrated it may not pick it up, the spot creatinine:microalbumin test is not as good as 24 hour urine but it accounts for hydration and is a fabulous indicator of kidney function. In fact, that is the test most will see an issue often years before creatinine moves.