I'm 37, male, fit/active. 6' 2", 190 lbs. I have Graves Disease (hyperthyroidism), but it's under control via methimazole and vitamin D3. As part of my routine labs for this, I do have kidney function tested. And over the last few years, there's been a declining trend in eGFR based on creatinine levels. BUT... every other test is normal. No protein/blood in urine. BUN is good, albumin is good, all the ratios are fine. Literally zero other biomarkers show an issue. Only creatinine. So I've also had cystatin c tested as it's an alternate marker for kidney function. If we go on creatine alone, then my nephrologists (I've seen two) say I have stage 2 CKD. Maybe even stage 3 at this point because eGFR is in the low 60s. But cystatin c tests show my eGFR is over 100, which it should be in a healthy person. Neither of the nephrologists I've seen know how to interpret these test results and neither one know what can cause a high level of creatinine—other than hydration levels, muscle mass, protein intake, etc. I'm no body builder. But I do work out a lot (rock climbing/lifting). Any advice?
CKD Diagnosis: Normal Cystatin C, but Abnor... - Kidney Disease
CKD Diagnosis: Normal Cystatin C, but Abnormal Creatinine
your creatinine levels alone are not always the best way to determine kidney function. Your creatinine level depends on different factors such as age, gender and body size. The best way to determine how well your kidneys are functioning is to have your doctor test your Glomerular Filtration Rate (eGFR).
Thanks. But I thought creatinine tests are how eGFR is calculated? Is there some other way to arrive at an accurate GFR? I've done 24-hour clearance tests, spot tests. Serum and urine. All sorts of tests and eGFR based on creatine in both my blood and urine indicate my eGFR is in the low 60s for the past two years. And most recent test is 58. But I did cystatin c test at same time and it shows eGFR is over 100. So which one do I trust? I'm not super muscular or anything, but I'm pretty active. Neither nephrologist I've seen can make sense of it.
I've noted this being debated on here previously without consensus and it appears your medics don't know the answer. But, cutting across that, I'd say the trend is more important anyhow. You've said the eGFR trend is declining but I'm unsure if the cyastin is (or how many times it's been tested)?
Cystatin c has been tested a few times. Each time contradicting creatine. Creatinine-based eGFR has been in the 60s for a year or more, while cystatin c eGFR has shown 90s and most recently over 100.
OK so theres an (unexplained) difference between the methods but it sounds like your kidney function is now stable either way which is comforting.
So I would ask, what is your creatinine?CKD is diagnosed by not only looking at your creatinine, urine tests, BUN - but seeing a trend over time. You have to remember that eGFR is but an estimate of your filtration rate. I know my nephrologist looks at my creatinine, BUN, other values rather than eGFR. Your levels and GFR can also be affected by your hydration, stress, exercise and what you ate the night before your labs were done. That is how they can be different from a lab draw last week and one done today.
When I have my labs done quarterly my eGFR my value is stated as >60.
When I was diagnosed, the nephrologist did not use GFR.
Cystatin C test is used to determine if you do indeed you have kidney disease. Depending on the doctor, he may use this test or a creatinine calculation.
I guess this goes to show you why your lab values have to show a trend and not just a one time thing.
All other serum/urine tests are normal. BUN, albumin, protein, glucose, phosphorus, all ratios, and everything else they test for metabolic and renal function. All normal. Only abnormal biomarker is creatinine. But here are my serum creatine results over the last three years: 1.35, 1.32, 1.30, 1.33, 1.33, 1.2, 1.34, 1.36, 1.36, 1.52, 1.2 and eGFR based on these results has gone from 77 to 58. Creatinine in a 24hr urine collection ranged from 3.03 to 2.11. One random (spot) creatinine test showed 269.94 mg/dL. Albumin/Creatinine ratio (urine) was 4 mg/g (normal is under 30). Another 24hr creatinine clearance test showed 131.84 mg/dL creatinine, per day was 32.81 mg/kg/d (high). Upper end of normal range given was 28. Most recent random metabolic panel showed creatinine (serum) was 1.52 mg/dL with an eGFR of 58.
The cystatin c tests I had done showed eGFR to be 94 and now currently it shows 107 (it's gone up), even as eGFR from creatinine has gone DOWN to 58. So it makes no sense to me or my doc.
I have the same issues. It has been demonstrated that elevated creatinine is a part of a bodybuilding lifestyle (mine is 1.60) so my gfr is around what yours is. My cyastatinC test came back with a gfr of 90 so it is confusing. So possibly your active lifestyle is yielding more creatinine than a normal "average" person would have.
Hi FourT6and2,I have an abstract of a study for you to look at. It might explain why you have low GFR based on creatinine and high GFR based on Cystatin C. According to article, thyroid function affects these kidney function tests. So if you were treated for hyperthyroid (and FT4 normalized) it can show increase in creatinine and decrease in Cystatin C. The opposite happens in people treated for hypothyroid. We’re your FT4 levels normal when they took the kidney tests, cause it seems that could be factor in thyroid disease ? This particular study didn’t favor using Cystatin C in thyroid patients, but other studies may favor Cystain C, or this is a bad study, I don’t know.
karger.com/Article/Abstract...
I’m not a doctor so I don’t know, this is why we rely on doctors expertise, but your doctors left you guessing. If the kidney doctors said they thought you have stage 2, then I would ask why do I have stage 2? Maybe talk to the nephrologist about hyperthyroid and what conditions of the kidney it could cause and if he can do other testing to determine that and what to do about it. Or alternatively could you have a cause that wasn’t hyperthyroid. Or no kidney disease at all and the tests could be confusing because of the thyroid issue.
I’m not saying you have kidney disease. Maybe the Cystatin C is accurate in your situation. However, the GFR testing with thyroid disorders seems complicated and you need a doctor that clearly understands it all completely. Also maybe talk to other people online with hyperthyroid/kidney issues and they probably will have experience with it all. Good luck!
Thank you for that! Yeah I asked both of my nephrologists and my endocrinologist (who treats me for my thyroid) if that could have something to do with it. And all three doctors told me that thyroid function has absolutely nothing to do with kidney function. And that my hyperthyroidism and its treatment can't affect kidney function, nor interfere with eGFR tests. I am suspicious of their answers though, precisely because I've read studies like the one you shared. When I share studies like these with my doctors, they laugh and tell me not to believe what I read online. So yeah... I'd love to find doctors I can trust and who are willing to do the legwork to figure this stuff out, but it takes 3-5 months to get an appointment these days, if a doc will even accept new patients. And that's literally just to get in the front door and have a conversation. Then they want to run all these same tests all over again to establish their own baseline. It's a broken system.
I'd be suspicious too. I've had experiences like yours with my own physicians. There has been times they were right, and times they were not. The way I look at it is even if they are right about the thyroid, they still need to explain this decreasing eGFR based on creatinine. If you are really in stage 2 or stage 3a, you need an answer to why so you can take measures to prevent further damage. Good luck and may you get the answers you need!!
I too have Graves Disease but luckily mine is in remission with no medication or god forbid removal of my thyroid. If I keep my stress levels low I can avoid another bout. I do have CKD with an eGFR of 22. I haven't had a cystine c test done but I wonder how that would affect a person's ability to get a transplant? Suppose I dropped to below 20 based on my creatinine levels and got accepted to the transplant list but cystine c showed I was at 30?
Can you try this test. It's weight, age and creatinine based.
mcw.edu/calculators/creatin...
I'm very small at 4'9" and 92 lbs so tests designed for "normal" sized people aren't accurate for me as my body mass is so much less. It's possible your body mass is greater and so the eGFR is incorrect.
I too have Graves Disease but it's in remission with no meds and they didn't do the radiation or remove anything. I put my foot down and refused and so far so good. I have no idea if there's a link between my thyroid and my kidneys but since the thyroid regulates all systems I have to wonder.
Oh and my FT4, FT3, and TSH levels are all normal and stable and have been for at least two years. But I'm willing to bet there is still some interaction going on between my thyroid issue and my kidney tests. But my doctors refuse to look into it. Specialists these days do not diagnose, nor do detective work. They only treat a pre-existing diagnosis that is handed to them on a piece of paper by a referring physician.
For those interested go read my replies, about 6 and they are long about creatinine, cystatin-c, eGFR and other measurements. The ASN actually renames their preferred method and recommended way to calculate an estimate of GFR without using creatinine or cystitis-c and they call it mGFR and it is much more accurate. Further the ASN really has been driving home the point to it’s members and has been trying to disseminate the information to all nephrologists or GPs who manage CKD patients the importance of only using e (or their preferred m) GFR and UACR for both diagnosis and following CKD patients due to as one of their many studies puts it, “the cutting edge new therapies to help stop or improve performance of newly diagnosed or current CKD patients.” See when all we had was diet and other passive treatments until dialysis and transplant inaccurate function tests like creatinine and cystatin-c were fine to watch stage 3 turn to 5 the dialysis. However, according the ASN the new treatments need a much more precise measure of function to pick or design the proper therapies for where each individual patient is kidney function wise.
I apologize for not posting but to gather and type all that info took me about 4 hours.and I don’t have the energy to do it all again. Especially when half the people will either tell me I am wrong because they heard, Joe Blow said, or their nephrologist who they have use and trusted for years doesn’t do all that the other half of the half of the folks remaining won’t tell me I am wrong for those reasons but will think I am wrong and blow it off.
I want to help and I have been CKD 4 for over 26 years. I am currently and will stay disabled so I have the time to dedicate 3/4 hours of research a day in order to become the best advocate for me as I can be. I understand most don’t have that kind of time or desire however, I do. I enjoying helping people as that was my job for more than 30 years of my life. Since I can no longer work I want to help others with CKD and osteoarthritis benefit from my ability to read and then copy and paste what I read so hopefully someone else can avoid a bad doctor or a life altering/ending complication. This is mostly what I do now. Also, I was extremely active here for about 6 months but had to take a 3 month break because frankly I got tired of the misinformation and then those folks getting upset when I went back with research links from reputable sites and just continue with the misinformation.
Finally, if you have the insurance that allows you to do it and live in the US I don’t know why you wouldn’t change docs to those using the most current science that may could intervene with the new therapies outlined on the ASN website it it could halt the progression of your CKD or keep you from going to dialysis ever in your lifetime much less avoid the transplant.
Hi Blacknight1989, thanks for the information and posts! I tried to look on the ASN website for new therapies, but I couldn’t find it. I want to read it. Would you mind posting a link?
My pleasure Sarah. Initially this link:
If that link only takes you to the main site home page than three choices of your desire. You can search new treatments/therapies for CKD and there will be 90-100 articles from “kidney week” that come up. All sorts of patients, diabetic, non-diabetic, dialysis, no dialysis, male, female, old, young etc.
Or
Option 2 from the menu at top select kidney health initiative and used the menu for whatever interest you.
Or
Option 3 menu at top and select KidneyX and this is the most exciting all the really new stuff…artificial kidneys, pig kidneys etc.
If the link above takes you to Kidney Health Initiative
Use the link below for the ASN home page.
A couple of hints on issues that may be unique to me. My iPad does not show the menu at the top of the home page where you have the choice to search, select KHI or KidneyX so you have to pull the page down. May need an extra click on a laptop. Under Kidney X use the menu button next to the search button on the right to go to the drop down. Under that menu select Artificial Kidney Prize and that will open a whole slew of information along with links to their partner organizations doing similar research.
Also don’t select you are a patient…much better information that way!
Let me know if you need additional information or help. Be glad to do what I can.
Thank you so much!
My pleasure
I did a google search for mGFR and oh my. Over my head but quite in depth. I have an appt with my nephr tomorrow and I'll bring this up.
Here is a link to the NIH site on kidney disease at NIKKD for an FAQ on eGFR. Might be a good place to start.
Oh the thread with all the info I outlined before I started feeling sorry for myself and went on a rant….MY Apologies…is “Standards for measuring Kidney Function.”
Do you have a link to that post?
If you work out a lot your creatinine can be high without kidney disease. Also if you consume a lot of protein.
Yeah I do both of those things lol
I was the same way. Heavy protein and heavy exercises daily. Once I let up on the protein and lowered blood pressure, and only lift 4 days a week my gfr went to 100. Muscle mass plays a part. Even if you are even slightly more muscular than the average normie it will throw you off of whats “normal”. My creatinine has been 1.10-1.20 for years
So is it bad or unhealthy to have higher than normal creatinine? Or is it simply a biomarker for a test? My blood pressure is fine. But let's say it is from eating too much protein and exercising a lot... and that leads to high creatinine on a blood test. Is that, in and of itself, bad?
It’s really circumstantial. I’m not a doctor so I can’t really speak on it but when I was at my most muscular of 260lbs with 10% body fat at 6’2, my creatinine was a bit higher than it is now. It’s been around 1.10 for me since a year after high school for me but when I gained a bunch of muscle it went up.
I wouldn’t say increased creatinine due to excess protein and exercise and muscle mass is “bad” unless you already have ckd. Well, maybe too much protein especially animal protein is not the healthiest….I’d just cut back on strenuous exec use and protein for a bit and see where your labs are. I cut back on lifting every day to 3 days a week and lowered my protein intake a lot and haven’t lost any muscle from what I can tell however I lost water weight and my bp went down to more healthy ranges
Makes sense, thanks
Try this calculator and make sure you adjust for body composition.
Read up and find out you most likely have no concerns currently. Link:
Proper way to diagnosis CKD.
Creatinine of 18, but kidney function returning. 
Egfr 71, slightly raised creatinine, stage 2 ckd or not?
MY CKD JOURNEY..FROM EGFR OF 11 TO EGFR OF 84.. FROM AKI 5 TO CKD 2.. STRUGGLING WITH LOW SODIUM LEVELS.
Has any one had this test before Cystatin C /Cystain 3
confused
