High Creatinine Levels

[JohnHelton]

Anyone else been flagged by the doctor for high creatinine levels? I've got a new GP, and he is all concerned given my 1.4 mg/dL reading. Wants me to see a kidney specialist. My creatinine levels have measured the same since I started lifting 5 years ago.

https://www.barbellmedicine.com/blog/ab ... -function/

[aurelius]

As I understand it from research I did many moons ago after receiving advice to stop using creatine by a doctor:
-creatinine is a by product of creatine usage by the body. Supplementing creatine will increase creatinine levels.
-High creatinine levels are an indicator of poor kidney function. The causal link between raised creatinine levels and kidney function is not fully understood.
-If a reasonable explanation for raised creatinine levels can be established (such as creatine supplementation) and there are no symptoms of poor kidney function, you are 99% okay.

[JohnHelton]

As I understand it from research I did many moons ago after receiving advice to stop using creatine by a doctor:
-creatinine is a by product of creatine usage by the body. Supplementing creatine will increase creatinine levels.
-High creatinine levels are an indicator of poor kidney function. The causal link between raised creatinine levels and kidney function is not fully understood.
-If a reasonable explanation for raised creatinine levels can be established (such as creatine supplementation) and there are no symptoms of poor kidney function, you are 99% okay.

From Austin's article linked above:

Another scenario may involve an individual who is very muscular. The higher level of skeletal muscle results in more creatinine production, and therefore a higher plasma creatinine level – without any change in GFR. This can be tricky in practice because the lab report may highlight the value (for example, 1.4–1.5 mg/dL) as being “out of range”, potentially raising a false alarm about a decline in kidney function. To be clear: the vast majority of individuals – even those who train – will not exceed 1.5 mg/dL or 133 umol/L in the absence of kidney impairment.

also this

The first consideration is whether there is a prior lab value available for comparison because this helps to characterize the degree of “abnormality” as well as the time course involved. For example, if an apparently healthy patient without any medical issues has a result of 1.3 mg/dL and it was the same 1.3 mg/dL five years ago, this stability provides some reassurance. Conversely, if an individual’s last measurement was 0.8 mg/dL and it is now 1.4 mg/dL, this should prompt further evaluation. This would be true even if they have gained some muscle mass from in the interim.

I would think I'm fine since my levels have been the same for 5 years, but I'm sure the doctor won't stop bugging me about it until I see the kidney specialist.

[quikky]

I would think I'm fine since my levels have been the same for 5 years, but I'm sure the doctor won't stop bugging me about it until I see the kidney specialist.

Assuming you don't have any actual symptoms of kidney impairment, I think you're fine.

[asdf]

Supplementing with creatine elevates my creatinine levels. So does intense exercise the night before an AM blood draw. So does dehydration. These are correlations I've experienced over the years.

[Philbert]

If it were my GP, I would try to persuade him to order a 24 hour creatinine before referring me. Kidney function is inferred from serum creatinine based on assumptions about 24 hour creatinine production. Proving those assumptions false would put the question to rest.

[Philbert]

I would think I'm fine since my levels have been the same for 5 years, but I'm sure the doctor won't stop bugging me about it until I see the kidney specialist.

Assuming you don't have any actual symptoms of kidney impairment, I think you're fine.

I also think he is fine, but I would hesitate to base that opinion on his lack of symptoms. Many problems are asymptomatic until advanced, and most functional humans are good at ignoring mild symptoms.

[Philbert]

As I understand it from research I did many moons ago after receiving advice to stop using creatine by a doctor:
-creatinine is a by product of creatine usage by the body. Supplementing creatine will increase creatinine levels.
-High creatinine levels are an indicator of poor kidney function. The causal link between raised creatinine levels and kidney function is not fully understood.
-If a reasonable explanation for raised creatinine levels can be established (such as creatine supplementation) and there are no symptoms of poor kidney function, you are 99% okay.

The causal link between creatinine levels and kidney function is both well understood and simple. Creatinine is produced by creatine metabolism as you said. It is filtered out by the kidneys and not re-absorbed. Failing kidneys filter less blood less effectively, thus filtering less creatinine, thus allowing the creatinine level to rise until the amount in a smaller filtered volume is equal to the daily production from creatine metabolism. The weakness of creatinine as an inverse proxy for kidney health is 1, the formula for normal uses age and sex to predict total body creatine metabolism, and 2, a healthy kidney regulates blood flow in response to conditions, so a dehydrated person will have a creatinine suggestive of kidney injury when the kidney is just doing its job and preserving blood volume by filtering less.

[aurelius]

The causal link between creatinine levels and kidney function is both well understood and simple. Creatinine is produced by creatine metabolism as you said. It is filtered out by the kidneys and not re-absorbed. Failing kidneys filter less blood less effectively, thus filtering less creatinine, thus allowing the creatinine level to rise until the amount in a smaller filtered volume is equal to the daily production from creatine metabolism. The weakness of creatinine as an inverse proxy for kidney health is 1, the formula for normal uses age and sex to predict total body creatine metabolism, and 2, a healthy kidney regulates blood flow in response to conditions, so a dehydrated person will have a creatinine suggestive of kidney injury when the kidney is just doing its job and preserving blood volume by filtering less.

The underlined was my major point. High creatinine levels do not cause poor kidney function. Thank you for the correct explanation.

[houzi]

Bumping this old thread since its fairly relevantto me.
I had a blood test a few weeks back, Doc highlighted that I had high creatinine, BUN and Uric Acid. However, I had all of my blood tests the less than 24hrs after a heavy lifting session.... Unbeknownst to me at the time, this can elevate all sorts of things and show false readings. My urine tests I had on the same day showed no blood or protein.

The past few weeks I reduced my protein intake a bit (reduced meat portions, im not using protein supps or creatine at aall and tried to make I was always hydrated.
Had another blood test this week, but was aware to leave it more than 48hrs after lifting this time.

Results show that my BUN was down to normal levels, and my creatinine and uric acid were reduced but still high (creatine down to 115 umol/1.3mg.dl). Im still a bit concerned about the uric acid level, but im wondering if i should be? I lift weights, im fairly muscular, high protein diet. Any thoughts or input welcome.

Also curious @JohnHelton if your tests also showed high BUN or uric acid?

[JohnHelton]

Also curious @JohnHelton if your tests also showed high BUN or uric acid?

I didn't have high BUN levels. If it has gone down, then I probably wouldn't worry about it. With regard to creatinine, those tests have a reference range for average people that don't really lift. My number went down on my latest test (January 30th) to 1.2 mg/dL. However, that was on a Tuesday morning before lifting, with my previous session being on Friday.

[houzi]

Also curious @JohnHelton if your tests also showed high BUN or uric acid?

I didn't have high BUN levels. If it has gone down, then I probably wouldn't worry about it. With regard to creatinine, those tests have a reference range for average people that don't really lift. My number went down on my latest test (January 30th) to 1.2 mg/dL. However, that was on a Tuesday morning before lifting, with my previous session being on Friday.

That is what im leaning towards, especially since there was a reduction across all 3. I dont have any symptoms of kidney problems, no kidney pain, no gout, plus no protein or blood was found in urinalysis either.

I think I will do another test in a few months, maybe try to time it so that I have 72hrs of no lifting prior.

[asdf]

My doctor knows I take creatine, lift, and do stupid CrossFit stuff, so he's typically not concerned about high creatinine levels in my results. But sometimes he orders a follow-up Cystatine C test. (Maybe he forgets about my lifting or creatine? Or maybe "best practice" dictates that he checks periodically?) Fortunately, when he does order the Cystatine C test, he does so immediately after getting my creatinine results, so that I don't have to go in for a second blood draw. Cystatin C always comes back normal.

[gymdad150]

Amongst all the other shit I've dealt with medically these past few years, an elevated Creatinine of 1.4 DEEPLY concerned my PCP.

I presented the Barbell Medicine paper, along with my past history of running a little high. He was concerned about my use of Creatine, and my ingestion of "high" levels of protein.

Ultimately, he insisted that I have am ultrasound study of my Kidneys.

That study came back completely normal in all aspects (plus it showed the size of my prostate, two years after radiation treatments, being of normal size which was gratifying).

He hasn't said boo since.

Someone up thread mentioned that digging deeper into the high number was just "best practices" by the PCP. I'd call it defensive medicine...but that's just me.

[aurelius]

Someone up thread mentioned that digging deeper into the high number was just "best practices" by the PCP. I'd call it defensive medicine...but that's just me.

I'd call it running up the charges on an insured patient to buy that 2nd house in Malibu.