I would agree, that is the formula I would use. This is very reassuring.

I am now going to be closing this thread as it has gotten a bit too unruly with everyone posting responses to it. Any future questions on new issues can be made using a new post.

Dr. Weinstein,

I wanted to follow up with you on my Cystatin C tests. My result came back as 0.6 mg/L. When I enter that information into the National Kidney Foundation website along with my Creatinine numbers, weight,, height, etc. I get the following results:

CKD-EPI creatinine equation (2009) 93 mL/min

CKD-EPI creatinine-cystatin equation (2012) 131 mL/min

CKD-EPI cystatin C equation (2012) 168 mL/min

MDRD study equation 83 mL/min

What do you think? I had previously read that the general consensus is that the most accurate equation to use is the equation that accounts for both creatinine and Cystatin, instead of just using one equation alone. That would be the CKD-EPI creatinine-cystatin equation 2012 from above that gives me a GFR of 131. I would like to know your thoughts. Thanks

It will likely be in the 90 ml/min range

Dr. Jordan Weinstein

I appreciate the fast responses. I'm sure you already think I'm crazy so what the hell, I might as well ask one more question. I have attached my GFR calculations from the Kidney Foundation website. I enter 1.24, my age, my height, my weight. The National Kidney Foundation recommends using the CKD 2009 equation, and that gives me a GFR of 93. When you say "I predict they will consistent with kidney function in the range of your current eGFR", are you referring to just greater than 60 GFR? Or do you mean they will likely be consistent with the 93+ GFR I get when on the National Kidney Foundation website? I only ask this because just over 60 GFR is kind of a good thing and kind of a bad thing. Patient results will come back as normal on panel test, but being only 39 years old, a GFR of just over 60 isn't very good.

They are mostly research level tests and not widely used. But they perform well and I predict yours will be consistent with kidney function in the range of your current eGFR.

Dr. Jordan Weinstein

Thanks. I know the Cystatin test are new and most people don't do them, but do you have any experience? If you did have to "bet", do you think my Cystatin results could still come back high and above the average range?

Jordan,

Good morning. When they drew my blood yesterday, they also did a regular panel test. Below are the results:

Report Result Ref. Range Units Status
CALCIUM 9.6 8.6-10.3 mg/dL Final A
GLUCOSE 107 75-99 mg/dL High Final A
SODIUM 140 135-145 mEq/L Final A
POTASSIUM 4.2 3.5-5.1 mEq/L Final A
CHLORIDE 104 101-111 mEq/L Final A
CO2 29 21-31 mEq/L Final A
BUN 18 7-25 mg/dL Final A
CREATININE 1.24 0.70-1.30 mg/dL Final A

The family doctor said it looks like my kidneys are functioning fine and there are no long term concerns.His results just show a GFR >60. When I enter this 1.24 number into the GFR calculator on the National Kidney Foundation's website, with my height and weight, it puts me at GFR 93. And this number really isn't considering anything for lean muscle. Plus, I did workout like 2 hours before the blood was drawn. My last microalbumin test came back at <12.0 mg/L. What do you think? This puts me into a pretty good place in my mind with this last test. I'm still waiting on the Cystatin test to come back, but like I said I don't really even want to look at it. If those results are high then its going to put me right back in the mind frame I have had for the last couple years and its very hard for me to live daily life that way. Also, just as a question on the microalbumin test, the creatinine to albumin ratio result came back as "unable to calculate", what does that mean and is the result of <12.0 mg/L for the microalbumin good?

That is great. No worries then. The microalbumin could not be calculated because the protein is so low in your urine that it cannot be detected. This is good!

Dr. Jordan Weinstein

Also, I wanted to add. The doctor said my glucose number was not concerning because I didn't fast before the test. Here are my numbers again, less jarbled:

Report
CALCIUM 9.6
GLUCOSE 107
SODIUM 140
POTASSIUM 4.2
CHLORIDE 104
CO2 29
BUN 18
CREATININE 1.24

Jordan,

Good morning. When they drew my blood yesterday, they also did a regular panel test. Below are the results:

Report Result Ref. Range Units Status
CALCIUM 9.6 8.6-10.3 mg/dL Final A
GLUCOSE 107 75-99 mg/dL High Final A
SODIUM 140 135-145 mEq/L Final A
POTASSIUM 4.2 3.5-5.1 mEq/L Final A
CHLORIDE 104 101-111 mEq/L Final A
CO2 29 21-31 mEq/L Final A
BUN 18 7-25 mg/dL Final A
CREATININE 1.24 0.70-1.30 mg/dL Final A

The family doctor said it looks like my kidneys are functioning fine and there are no long term concerns.His results just show a GFR >60. When I enter this 1.24 number into the GFR calculator on the National Kidney Foundation's website, with my height and weight, it puts me at GFR 93. And this number really isn't considering anything for lean muscle. Plus, I did workout like 2 hours before the blood was drawn. My last microalbumin test came back at <12.0 mg/L. What do you think? This puts me into a pretty good place in my mind with this last test. I'm still waiting on the Cystatin test to come back, but like I said I don't really even want to look at it. If those results are high then its going to put me right back in the mind frame I have had for the last couple years and its very hard for me to live daily life that way. Also, just as a question on the microalbumin test, the creatinine to albumin ratio result came back as "unable to calculate", what does that mean and is the result of <12.0 mg/L for the microalbumin good?

I completely understand.

I am a doctor and have lots of anxieties about my health too. I get it.

The test will likely be just fine. And if it isn't, ignoring it is not a great idea.

Jordan

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.

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

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?

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

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?

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

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

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

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

Are these the bubbles in the urine that can indicate that the kidneys are not working