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  1. Wendy
  2. General Nephrology Questions
  3. Friday, 12 October 2018
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Hello
Three weeks ago I had bloodwork done and my creative level was 1.29 and non African level of 45 I had a follow up test done again and my creative rose again 1.33 and non African dropped to 44 it has been continuously dropping since the beginning of the year should I be worried
Responses (30)
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Hello,

A change in GFR from 45 to 44 ml/min is not significant. A lab test such as creatine can vary with 10% from one measurement to the next. I would only become concerned if was persistently falling.

Dr. Jordan Weinstein
  1. more than a month ago
  2. General Nephrology Questions
  3. # 1
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It has in April it was 55 in September it was 45 and Tuesday it was 44
Creatine levels are rising as well 114 april, September 129 and October 132
  1. more than a month ago
  2. General Nephrology Questions
  3. # 2
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It has in April it was 55 in September it was 45 and Tuesday it was 44
Creatine levels are rising as well 114 april, September 129 and October 132


Those changes are significant. Have you had any recent illness or started any new medication - including over-the-counter or supplements?

Dr. Jordan Weinstein
  1. more than a month ago
  2. General Nephrology Questions
  3. # 3
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No my medication hasn’t changed and my doctor doesn’t say is a problem but I have had a constant side ache for about three month I know that that’s not were my kidneys are but I worry about colon ca my dad had that
  1. more than a month ago
  2. General Nephrology Questions
  3. # 4
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You might consider having an ultrasound done to exclude a kidney stone on the painful side. As for the change in eGFR, it is slightly more than one expects from laboratory fluctuation alone. A detailed physical examination and assessment of your urinalysis are warranted provided that the eGFR change persists.

Dr. Jordan Weinstein
  1. more than a month ago
  2. General Nephrology Questions
  3. # 5
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Thank you Dr. Weinstein, I did have an ultra sound and the impression noted multiple subtle exhogenic foci bilaterally maybe ? Vascular calcification less likely renal stones without hydronephrous not seen previously 10/16. I am just worried that my doctor isn’t taking any precautions to stop the decline of my kidney health
  1. more than a month ago
  2. General Nephrology Questions
  3. # 6
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The ultrasound might have detected kidney stones but as you wrote above, it is not conclusive. I think you would be correct to want to investigate this further. It is however reassuring that GFR has not declined over a 1 month period.

Dr. Jordan Weinstein
  1. more than a month ago
  2. General Nephrology Questions
  3. # 7
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Doctor,

I just wanted to put in my two sense and see what you think. I think that lab calculations of eGFR in most labs is totally inaccurate. Most labs use the standard MDRD formula to calculate eGFR. This equation is a standard equation that does not take into account for muscle mass, weight, height, etc. It is a formula that uses the average height and weight for the average male from the 1920s! It has been stated that the MDRD equation can be off by 29% in healthy patients. The National Kidney Foundation suggests using the CKD-EPI Creatinine Equation (2009) to estimate eGFR. This equation takes into account height, weight, age, etc.

I have been worried about my kidneys now for the last couple years. I'm 39 years old white male, 6'3" tall and weight 205 lbs. I weight train six days a week. I USED to take creatine suppplements. About two years ago I went in just to have a simple check up. They ran my blood and my GFR came back at 38! I was totally freaked out. The doctor told me to quit taking the creatine supplement and come back in two weeks. After two weeks, I tested again and my GFR was 58. The doctor said it was improving and I should be fine. Since then I always have had this worry that something is wrong with my kidneys. I constantly look at the toilet after urinating to see if there are any bubbles or foam. I have had blood work done 4 times since them and had about 3-4 urine tests. They have never found protein in my urine from urine tests. I also had microalbumin tested and it came back "unable to calculate" with my microalbumin reading being <12.00 mg/L. I also had CT scan of my kidneys and also had a CT scan of kidneys where they used contrast dye. The radiologist stated that kidneys were functioning well for filtering the dye. I also had an ultrasound done on my kidneys and came back as normal. I have seen several doctors and even went to a renal doctor, which by the way wasn't available so they had me see a nurse practitioner instead who works in the renal office. When I was visiting that nurse, they did my bloodwork and my Creatinine came back as 1.36 and GFR was like 58 again. During all of this, my follow up tests have basically came back in this range. My very last test that I had done about six weeks ago came back at Creatinine 1.26 and GFR came back as normal (which means it was above 60 GFR). With that said, the renal nurse at that time actually diagnosed me with Stage III kidney disease, so of course this freaks me out even more. Their lab uses the standard MDRD equation. I began to do more research online and came across the National Kidney Foundation and the CKD-EPI equation that they recommend to use. Also found several other sites that state that the MDRD equation is outdated.

So, here is my question for you. When I enter my numbers, height, weight, age, into the CKD-EPI equation I get GFR of 91, which for my age the range is 90 to 100 for normal. Furthermore, I did even more research on why there is an option to select African American or non African American when using these calculators. I found out that the reason for this is because most African Americans of the same size, age, and height have an average of 20% more muscle mass than other races. So, this is something that I also should consider or else why would there be this option? Muscle mass does make a difference or else it would not be an option when calculating GFR. I'm not the average muscle mass of someone the same race, age, and size. I'm pretty lean and have larger than average muscle mass from weight training. So, if I check the African American box on the GFR calculator, I come back at 106 GFR. But for argument sake, lets just say I'm not the 20% more muscle mass and take half of that, my GFR would be 98.5. Do you think that the way I'm looking at all of this and trying to calculate my GFR is accurate? To me, it seems totally reasonable to use the height, weight,and muscle compostion of the person actually being tested, and not to use the height, weight, and muscle composition of someone that is much smaller. Lastly, I do eat a higher protein diet which I have read can contribute to higher creatinine levels along with muscle breakdown from working out almost every day.

I guess I'm looking for your opinion here as it worries almost every day. Most of the doctors I have seen (except for the renal nurse which is very surprising) say that I'm fine and to quit worrying about it. It just amazes me that these generalized equations used in many labs are not more specific and may be wrongly diagnosing people with kidney disease?
  1. more than a month ago
  2. General Nephrology Questions
  3. # 8
Accepted Answer Pending Moderation
I think that you have correctly identified some of the important limitations MDRD formula. These calculations, as you rightly point out, are population-based and do not always perform well at the extremes of body composition. In your case, since you may have more muscle mass than the average person, the formula may not perform well at all. Therefore, as you appear to have relatively normal kidney function based on your current creatinine level, I would track that number over time versus trying to compute your actual GFR. If your creatinine is unchanged over time, your kidney function is not deteriorating. The only way that statement would become untrue is if you markedly lost muscle mass and your creatinine remained the same in blood- because as you have pointed out if you're muscle mass is lower, for the same level of kidney function, your blood creatinine level should be lower as well. I would also take into account the level of urinary protein that you have, ensuring that is normal as well, to round-out the assessment.

All of that said, you are right, screening formulas for kidney dysfunction are far from perfect.

Dr. Jordan Weinstein
  1. more than a month ago
  2. General Nephrology Questions
  3. # 9
Accepted Answer Pending Moderation
Hello
These facts are interesting, I don’t have much muscle mass so I confused on establishing whether the test they use to determine if you have a kidney function disorder needs to be changed or researchers need a different formula to have proper reading My next blood work isn’t due till February of next year should I have one in between before 2019?

Thank you for giving so much insight with these comments from you and other guest.
  1. more than a month ago
  2. General Nephrology Questions
  3. # 10
Accepted Answer Pending Moderation
Are these the bubbles in the urine that can indicate that the kidneys are not working
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  1. more than a month ago
  2. General Nephrology Questions
  3. # 11
Accepted Answer Pending Moderation
Hello
These facts are interesting, I don’t have much muscle mass so I confused on establishing whether the test they use to determine if you have a kidney function disorder needs to be changed or researchers need a different formula to have proper reading My next blood work isn’t due till February of next year should I have one in between before 2019?

Thank you for giving so much insight with these comments from you and other guest.



Actually Wendy, at your level of kidney function (under 60 ml/min), the eGFR test does perform well. It's in patients with GFR above 60 where its accuracy has been questioned.

Dr. Jordan Weinstein
  1. more than a month ago
  2. General Nephrology Questions
  3. # 12
Accepted Answer Pending Moderation
Thank you Dr Weinstein,
I did just up-load a picture and I noticed bubbles so I guess I am wondering if I should have a blood test again before February
Also I was reading an art about another test that they can use and said it was more accurate but may cost a bit more. Have heard if cystatin c test

Thank you
Wendy
Attachments (1)
  1. more than a month ago
  2. General Nephrology Questions
  3. # 13
Accepted Answer Pending Moderation
Thank you Dr Weinstein,
I did just up-load a picture and I noticed bubbles so I guess I am wondering if I should have a blood test again before February
Also I was reading an art about another test that they can use and said it was more accurate but may cost a bit more. Have heard if cystatin c test

Thank you
Wendy


At a GFR below 60, the eGFR is likely accurate. The cystatin c assays and related GFR calculations are not widely available but if you have access to them, it might give you greater confidence in the reading you are getting.

Dr. Jordan Weinstein
  1. more than a month ago
  2. General Nephrology Questions
  3. # 14
Accepted Answer Pending Moderation
Are these the bubbles in the urine that can indicate that the kidneys are not working


In the absence of abnormal protein levels in the urine, bubbles are not concerning.

Dr. Jordan Weinstein
  1. more than a month ago
  2. General Nephrology Questions
  3. # 15
Accepted Answer Pending Moderation
Dr. Weinstein,

I wanted to follow up on this conversation from my post above. I called my doctor today and had him schedule me for a Cystatin C test. I went in and gave blood about an hour ago. I'm the typ of person that worries everyday about this since the renal nurse practitioner diagnosed me with Stage III kidney disease based on my creatinine GFR. As I discussed above, I didn't think this was accurate based on the equation used that didn't account for height and weight. Now that I have given blood for the Cystatin test, I'm getting very nervous again that maybe I did the wrong thing. I was at a pretty good place with my GFR coming in at 91 when using the National Kidney Foundations equation where I enter my height and weight. But in the back of my mind, I always was a little worried because I'm basically using my own findings and calculations for GFR that goes against what my renal nurse stated. I mean your renal nurse/doctor would be the one you trust, right? So I asked my Family Doctor to schedule me a Cystatin test as most research shows that Cystatin test are independent of height, weight, muscle mass, etc. But now I'm worried again. If these results come back with elevated Cystatin numbers, I'm totally going to freak out and lose my marbles. I think this is partly because after I got back from drawing blood, I read about a study that was done where testing of Creatinine and Cystatin was done. Out of 600+ patients, only the CKD diagnosis of 7.7% of those patients was changed from CKD to non-CKD diagnosis. About 30+% of the patients actually ended up with a lower GFR after the Cystatin testing. I don't know. What do you think?
Accepted Answer Pending Moderation
Hi there,

I would not be concerned. The CKD staging system is very imperfect. If your GFR is consistent with the levels you indicated before and if your creatinine is not changing and urinary protein and blood pressure are normal, I really would not be concerned. I can't say "don't worry" but I am confident you don't have to based on what you indicated above. Feel free to monitor it and if things change, you can re-evaluate, but at this point, I see no red flags.

Dr. Jordan Weinstein
Accepted Answer Pending Moderation
Thank you for responding. I was actually thinking about not even looking at my Cystatin results now. Are you saying you think that my Cystatin results will we within the normal levels?
Accepted Answer Pending Moderation
Are you asking me to bet? :)

Based on what you have indicated above, yes, I would expect the GFR based on cystatin C to be relatively normal.

Dr. Jordan Weinstein
Accepted Answer Pending Moderation
Thanks. You probably think that I'm crazy, but I have two small children and worry about this daily. For example, when I urinate in the morning and sometimes throughout the day I sometimes have more bubbles/foam. I then think there is a kidney problem. I try to tell myself that I should not worry, but its hard to do. I think the thing that really set this off was when my renal nurse actually diagnosed me with Stage III. I have never had any health issues, so that was a blow to the face. Ever since then I have been reading and trying to figure out everything possible if this diagnosis is false, hence the reason I'm still pursuing and scheduled the Cystatin C test. I'm pretty confident now on your responses along with what I figured out on my own, that I'm ok. So wondering if I should even look at the Cystatin results. If those show anything other than normal, it would be devastating to me. I was probably stupid to even have it done.
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