The entire egfr calculation, formula, has been questioned by many here and by every doctor I know. But now I found an even more strange calculation. The eGFR is basically taking your creatinine level (which indicates how well your kidneys are filtering creatinine from your blood), then calculating that with your sex, race, age, and thereby producing a eGFR. It is also said that even people with 100% perfect kidneys, as we age our eGFR will reduce. This implies that our kidneys fail to filter creatinine as much as we age. But this confuses me. If you look at my case. My creatinine is 1.7. Has been for 18 months (due to one kidney removed). So at my age (68) I get an eGFR of 41. This month I turned 69. That is all that is different. One month older than last month. Creatinine still 1.7. But now my egfr becomes 40. Down one. So I tried future ages, such as 70, it will be 39, at 73 it will be 32. YET the creatinine level remains constant at 1.7, so the kidney is doing the same amount of filtering as it always did. The kidney performance is not really reduced. Still 1.7. But I gradually move toward stage 2??? This makes no sense to me at all. One would expect that if it is normal for our eGFR to decline with age, you would expect that is caused by our Creatinine level increasing, due to declining kidney function. But no. With this crazy formula approach just because you age another year, you suddenly can go from moderate kidney function to severe. I have no faith in this formula whatsoever. It's crazy.
eGFR Confusing Changes with Age - Early CKD Support
eGFR Confusing Changes with Age
I couldn’t agree more! My sole kidney function never presented any declared problems.....until this creatinine formula for arriving at an eGFR figure came on board. Even the very title ‘Chronic Kidney Disease’ is weird - it isn’t an actual ‘disease’ at all! I queried this title with a renal consultant some years ago. His reply: “The Americans have given it that title and we have to live with it”. I live in hope of another more exact science formula being found!
The formula also factors your BUN number as well which can fluctuate based on diet and hydration. I wouldn't worry too much about a digit up or down. You will be driving yourself crazy otherwise. 1.7 is normal for a solitary kidney to be honest.
Actually I do not think BUN is a factor. If you look at all the different calculators on the internet (here is one example, but they are all the same ukidney.com/nephrology-reso..., they simply as your Creatinine level, age, sex, race. In fact that is one of my complaints that more things are NOT considered, such as BUN. And also such things as your hydration level, etc. These are all considerations that SHOULD be looked at before labelling someone with a disease. To be very technical here is the actual formula for determining eGFR: 186 x (Creatinine/88.4)-1.154 x (Age)-0.203 x (0.742 if female) x (1.210 if black). It is just crazy :). Yes I am in total agreement that 1.7 is normal for one kidney. The trouble is I go to 5 doctors of different specialties. Two (oncologist and heart) tell me 1.7 is normal. Urologist will not commit. Kidney doctor makes no comment except to point to a chart that says 1.7 for my age is CKD 3b and to have a nice day!. My GP tells me having one kidney should make no change in Creatinine level, which at age 69 is simply ridiculous. You are so right that up or down one point is nothing. My point it, if the creatinine level remains constant (1.7), just getting one year older lowers your egfr based on the formula which can move you from one stage to the next below. Yet your kidney function has not changed. As my oncologist tells me "throw the entire egfr thing out the window". Just keep your creatinine level constant (whatever it may be) and monitor your Bun/Creatinine level (keep it in normal range). This tells you kidney function far better than any formula or chart of egfr. And as you say this factors in the BUN (ratio) which is important.
You're quite right about BUN not being in the formula, my mistake. As to your other comments I agree as well. I have seen GFR numbers go up 5 points in hospital and clinical settings just by having IV fluids introduced for two or three hours. Yes, GFR and BUN numbers that hold steady or do not trend negatively should be the ultimate goal. I was born with one kidney and had normal creatinine and BUN levels for 50 years which were normal for two kidneys. I do understand however that most people who are CKD 3b-5 fixate on the GFR as it is the gatekeeper for most dialysis and transplant list decisions. I am lucky to have one of the top nephrologists in the US on my case and he takes everything ( BUN, Creatinine, Albumin, Creatinine/Albumin ratio, BP, H1AC, etc. ) into consideration which of course is what should be done by a thorough professional. The specialty syndrome in modern medicine gets tiresome as well.
And it does weird things for my confidence. I’ve two kidneys and have my first appointment with my nephrologist late January. My egfr is 55 and has dropped over 18 months (maybe more time than that) and of course you start to panic, read stuff etc. I’ve already changed my diet, stopped booze, and increased exercise to 5 days a week. As a result I’ve lost 15lbs and feel much better for it. BUT....I’m scared witless to go get my bloods done in case the numbers change. Living in fear of numbers is doing my head in....
I have that same fear of numbers! From the time I get my lab til I get the results on my phone, I am paranoid of the numbers. I know my doctor takes other things into consideration, I just don’t what they are! My GFR is 8 and I’m not on dialysis yet.
We are the same. Also as Bunkin writes too. I go for blood again in about two weeks. It is on my mind constantly. And the time between the taking of blood and then getting the results I am on the computer every moment looking for the results to be posted. I know it is stupid because the numbers will be what they will be, but yet I am what I am and this is how I react.
I hope your appointment goes well. I find my appointments with the kidney doctor are basically of no use. For my first appointment I was nervous as could be. Worried sick. It ended up to be useless. She did nothing more than what my regular GP and Urologist had already done. Took blood and urine sample. Reported the result (which was same as GP, etc.). Told me to watch my diet (exactly as you have already done), walk (exactly as you have already done), and to have a nice day. See you in six months. That appointment was the same. etc., etc. She added my egfr will decline as I age. Impossible to make any prognosis. About numbers. Mine dropped to 35, then 40, then back to 36, then to 41, and have remained in the 38 to 41 range. I changed diet and walk. Lost 30+ lbs. But not a day passes that I do not have worry
My kidney doctor is amazing. I had a very large stone that he feels wreaked havoc and basically destroyed a kidney. I watch my diet, exercise, no vitamin supplements. I keep track of blood pressure. It is essential that my bp stay very good. No painkillers, several things to watch. A renal scan can be done to give you a better idea. My gfr is low, but went up a point after stone, and after stint. I have read kidney disease is affecting 38 million and most don’t know. From reading things on here, I feel many doctors really don’t know a whole lot about chronic kidney disease.
Hello RickHow,
Thank you for explaining the mysteries of the eGFR figures so well. For a long time I seemed to be the only one on this site who was never told this figure, by either my GP (as doctors are known in UK) or by the renal department's doctor at the local renal unit. I have asked several times but been told that its best NOT to know since it fluctuates all the time, and I would only worry about it all the time! Luckily, I recently saw another GP at the practice, who listened to my request and told me it - eGFR40. At last I have something approximate to act on!
I have been following the dietary ideas recommended by my researches into lowering my potassium levels (which I was to do, but not given any advice about how to do it). I have also been greatly helped by various posts on this site, but of course have no idea if I have been able to improve on the eGFR figure or not. I will carry on with my kidney-friendly diet as I am convinced it is the best way forward - the older I get (now 77) the more arduous life would become - I actually feel fitter now than I did 10 years ago, helped by a weight loss of 35lbs so far.
I think it best not to worry too much over these lab results but just to do the very best we can with diet, abstinence from smoking and alcohol, and exercise, but make time to do things we enjoy, like hobbies, socialising etc. - which cuts the stress too. Best wishes and Compliments of the Season to everyone - Curleytop1
I have read too that lower potassium is good idea. But it is hard to find how to. I just usually look at the food labels and see if it tells me anything about potassium level. I admire what you say about living life (things we enjoy, hobbies, etc.). You are 77. I am 69. Even without this so called kidney disease this is the type of lifestyle we should be living anyway (things we enjoy, etc.) because even without the disease we never know what tomorrow might bring due to our age. For potassium I'm told to limit bananas, raisins, oranges, tomato products and sauce. Notice LIMIT, not Eliminate. I still have some type of Italian dish (sauce, manicotti, spaghetti, etc.) once a week.
In my case, my eGFR dropped four 'points' from 58 to 52 in four months; that prompted my doctor to say I have a new baseline. Still Stage 3, though, and nothing else has changed. I agree that it's the age that's being factored in to the equation that makes it appear your kidney is functioning less well, when in reality it appears to be doing the same job for you.
I'm sure it was not good news to hear of the drop. However I have had similar in my past. Then the next test it was up 2, then next up 2 more, then next down 3....I have given up on it. I follow the advice of my oncologist (who I have much more faith in than my kidney doctor and my urologist). She tells me to throw away the egfr. Watch my creatinine level (want it fairly constant just changing one point up or down), and most especially my bun/creatinine ration (to her this show kidney function and is really what matters most. it is best indication of how kidney is filtering. it will go up or down based on hydration, but not significantly. If it is in "normal" range over time, all is fine).
Hey Rick, I also have more faith in my Oncologist as well. Mine is very caring, attentive and just a awesome person.
I went to see my Nephrologist last week. During my session I asked her about my Bun/creatinine ratio. She proceeded to tell me that that was not important because if that was fractured in , she would be out of business. I could hardly believe she made that statement. I am trying to and had been trying to find another Nephrologist. Not an easy task. Take care
Well then it seems what my oncologist tells me is correct about the importance of the bun/creatinine ration being more important than anything. My oncologist too is like yours, caring, etc. But I am also impressed that while she concentrates on cancer, her knowledge of kidney, CKD, etc., is more impressive than any of my other doctors. AND when I review with her what the others say but do not explain to me why, she sits with me and goes over every piece of data. And is not afraid to openly say that something one of the others tells me is not correct! I think your kidney doctor was correct she would be out of business. My oncologist gave me a list of how to maintain my bun/creatinine ratio. It was EXACTLY what we read on here so often about how to "treat" our CKD. All this egfr stuff could be thrown out and just watch the ratio. Here were the top items on that list (which is what the kidney doctor would say too for CKD). Exercise but moderately. Take no supplements and avoid anything containing excessive creatinine. Reduce your protein intake. Eat some fiber daily. Drink plenty of fluids. etc.
Hi Everyone!
I hear all of you. Everytime I have labs completed, I sit on edge.
All explanations here are great. Unfortunately, not all doctors or consultants take the time and effort to explain labs to their patients in detail.
The egfr and gfr will fluctuate from visit to visit. Additionally, the time of day the sample was taken, hydration, who was doing the spinning play a role in the results. Results will vary from lab to lab as well. My GP is with one group and my nephrologist another; their results will differ.
I am brazen as I ask.
Here is the description from the American Kidney Fund:
What is eGFR?
eGFR is short for estimated glomerular filtration rate. Your eGFR is a number based on your blood test for creatinine, a waste product in your blood. It tells how well your kidneys are working.
The eGFR is a good test, but it’s not right for everyone. For example, this test may not be accurate if you are younger than 18, pregnant, very overweight or very muscular. Talk to your doctor to find out if this test is right for you.
How do I know my eGFR?
You will have a blood test to see how much creatinine is in your blood. Creatinine is a waste that comes from your muscles. Healthy kidneys take creatinine out of your blood.
Your doctor will figure out your eGFR using the result from your creatinine test, your age, your gender and your race.
What does my eGFR mean?
A normal eGFR is 60 or more. If your eGFR is less than 60 for three months or more, your kidneys may not be working well. If you eGFR is below 15, you may need to start dialysis or have a kidney transplant. Use this scale to see what your eGFR may mean.
No matter what your eGFR is, ask your doctor when you should be tested again and what other tests you should have. Your doctor may want to look for other signs of kidney problems by doing more testing. These tests might include:
Urine (for protein or blood)
Blood (for other wastes)
Blood pressure
Blood sugar
What should I do next?
If your eGFR was less than 60, talk to your doctor soon!
If this was your first eGFR test, you may need to be tested again in a few months. Your doctor will want to see if your eGFR is less than 60 for three months or more. Ask your doctor when you should be tested again.
Whether your eGFR is above or below 60, you can take steps to keep your kidneys as healthy as possible:
Keep a healthy blood pressure (less than 120/80 for most people)
Control your blood sugar if you have diabetes
Follow a low-salt, low-fat diet
Exercise at least 30 minutes most days of the week
Keep a healthy weight
Do not smoke or use tobacco
Talk to your doctor about medicines that might help protect your kidneys.
© 2018 American Kidney Fund, Inc. All rights reserved.
I agree with Curlytop; eat clean with kidney friendly foods; drink your water and exercise to begin.
Just be mindful of sodium, foods which are high in potassium and phosphorus; consuming in moderation and red meat. Best place to start.
We are all in this together.
Wishing everyone in both Kidney Communities a wonderful holiday season filled with love.
Things may not be perfect but count the small things; they are a blessing.
Bet
My last visit to my nephrologist they had a power failure and he had my current results but not my previous results and I told him I had my previous results and the only thing he wanted to know was the creatine, so I figure that was the most important thing to him.
The answer to your question is simple. The formulas used to calculate GFR (and there are still a few - no one can yet agree if they are accurate) - are all using creatinine, age, sex (m/f), and race to calculate GFR. The only biological variable here is creatinine - and that isn’t very reliable either.
So yes, as you get older, the formulas for GFR estimate a lower filtration rate. BUT, this (quite incorrectly) uses age as it ASSUMES that your muscle mass decreases with age. It has nothing to do with creatinine. Creatinine is a very big “guess” on its own.
Thanks. Yep I understand what you are saying. My point is how ridiculous this formula is. One of the (and just one) of the criteria in accessing kidney function is the amount of creatinine left in your blood. And in my mind, if that remains constant over time, just because you get one or a few months older, yet have a constant creatinine level, should not then automatically move you closer to the next "stage" of your disease. For example, let us say a person has a creatinine level of 1.6 or 1.7 at age 70. And is classified mid stage 3 (3b). Now nothing changes over the years. Their creatinine level remains about 1.6 or 1.7, the bun/creatinine level remains about the same, no protein in urine, etc., etc. But then in just a few years they are classified stage 4 or worse, just because they are older. As you indicate the formula should take into account other variables. Height, weight, other medical conditions, etc. For example in my own case, using the "standard" formula I am classified with egfr around 40. If I use another available formula where you can enter your height and weight, I am classified egfr 45.
Yes, but there are even more than one standard formula these days. Thats how confused medicine appears. I recall a recent blood test where my creatinine-GFR was stated at least 3 different ways to appease all the Drs out there. I dont think it appeased anyone.
lol, I had an even more interesting one. Using the typical formula. One day I had my blood tested by gp. My creatinine was 1.7. The next day the oncologist tested my blood. Same creatinine level 1.7. They are both part of the same hospital and send blood to the same lab for creating report. The gp reported the egfr 2 points higher than the oncologist did. Same creatinine level, same age, same lab, different egfr's. The oncologist report matched what I calculated using the different internet calculators. Seemed right. The gp was not. I showed him the differences. His reply? "hmmm".
These calculators are always being discussed in the literature - whether they should factor .9996 for each year you age or .9997. I made up those numbers, but you get the idea.
They’ve been doing this for almost 20 years and haven’t yet realized that if they can’t get it to a consensus, that maybe they may be going in the wrong direction.
What gets to me the most is the use of serum creatinine as this indisputable measure of kidney function. That would be similar to taking a glass of water, dumping a specific number of ice cubes into it - coming back later and measuring the temperature of the water remaining in the glass to determine exactly how warm it is in the room where the glass is sitting.
That’s actually amore precise “indirect measurement” than GFR. I would be open to taking this stuff more seriously if the whole scheme had more sense to it. Any grading system that can call Stage 1 or Stage 2 “early CKD” makes no sense to me. Stage 1 is absolutely absurd, and stage 2 has little to take seriously. Do physicians even tell people that they have Stage 1 CKD?
i totally agree with you on this crazy calculation. i plan to discuss this w/ my nephrologist at my next visit on 1/8/19
I do know (or at least been told) that an eGFR in the "near" normal range can be way off. My doctor says he pays zero attention to egfr's around 60. He looks immediately for other signs like protein or blood in urine, BUN numbers, overall health, blood pressure and so on. I had a eGFR of 64 and was concerned but all my other test were completely normal. He said I 100% do not have kidney disease. No need for a follow up, no need to change diet, no need to do nothing. I still wasn't convinced so I paid money to consult a doctor from the Cleveland Clinic. He looked at my test results and 100% agreed that no kidney disease was present. I asked if because my eGFR was on the low side if that made me more prone to kidney problems later on in life. He said absolutely not. Both docts say my chances of getting CKD with a 64 GFR was the same as someone my age with a 100 gfr. Still unconvinced I retested in 3 months and found my eGFR was way up to 78. And looking back at past blood work my eGFR was 62 when I was 38 years old, 88 when I was 42, 107 when I was 44, back down to 60 when I was 45, then 64 when I was 49, and then three months later it was 78. So yes, creatinine levels are a horrible way to TRY yo diagnose CKD
I don't think they refuse to object, but rather they simply don't care.
I know this thread has been out here for a while but wanted to tell my story. Last year my eGFR came back <60, so my GP sent me to a nephrologist who told me I had kidney disease and would need to make a lot of lifestyle changes. I was in shock and spent the weekend in a panic attack. On Monday I went to my GP to get medication for the panic attack i was frozen in. He incidentally ran my creatinine number again and my eGFR came back normal. No kidney disease, no need to see the nephrologist again. Forward 3 months and I get tested again and my eGFR number is bad again. My GP wants me to go to a nephrologist again. My anxiety is back and I am thankful I have leftover xanax from the last time. I have asked for a different nephrologist, we will see what this one says.
First, remove your panic. As you have read all the posts in this subject you can see all the complaints about the egfr measurement. How it causes so many to panic, without cause.
You seem to be floating between getting just under 60 egfr, then back above, etc. It is very normal for egfr to bounce around. Yes find another kidney doctor. One who will explain to you first what stage of kidney function you are at. Here is a link which include a good chart to help you understand : kidney.org/atoz/content/gfr
Keep in mind, as you look at the chart that people with a egfr of even 90 are labelled as CKD. Simply ridiculous. And notice that even if you do have a kidney "problem" with your egfr of 90 it is considered MILD.
But most of all I would think either your regular doctor or your kidney doctor would want to do some testing. To see if this is normal kidney reading, or being caused by some condition. For example a cyst, or urinary blockage, etc.
Last you do not give your age. But remember kidney function does slowly deteriorate with age. And it is not a disease.
Most general practitioners will not even refer a patient to a kidney doctor with a egfr that is as yours. Your doctor is being quite cautious.
To make this even more distressing is I am a body builder. I am 50 years old but have more muscle mass than most 25 year olds. I found out recently that eGFR reports wildly invalid numbers for athletes. When i first went to the nephrologist he told me to give up protein and all supplements. This seems to have made zero difference in my eGFR but it has caused me to lose 15 pounds of muscle. I know it is muscle because my percentage body fat has been stable at around 10% for decades. I feel like he is actually destroying my health rather than helping.
Ah, that explains a lot. People such as yourself will have lower than typical egfr. Because muscle creates more Creatinine. More Creatinine, will cause the formula to say you have "abnormal" kidney. It is typical for a kidney doctor to say to reduce your protein and all supplements. That is told to every patient. I'm no doctor. But if you are as muscular as you say and workout so frequently that explains your egfr. I doubt very much you have kidney disease. It surprises me your normal doctor even sent you to a kidney doctor with an egfr of 60. But even more surprising is that the kidney doctor did not explain your reading is because of so much muscle and exercise. Look at your blood tests. If everything comes out normal, and the only abnormality is high creatinine level, if it were me I would not change my habits at all. If your urine tests come out all normal, this is even further illustration to not change habits. But watch your creatinine level. If it drops in the range it is in, over the next couple of blood tests, then it probably is time to drop the muscle, lose the weight.
I have the feeling that this whole eGFR calculation was created by the medical industry to bilk more people out of money and has little to do with health of the patients. I read online that the current standard put 14% of the population in stage 3 CKD but less than 5000 people a year are treated for end stage renal failure... so millions of people are diagnosed with CKD who will never even have protein in their urine, let alone need dialysis.
I'm not sure of why this formula was adopted but as your statistics reflect, it is a highly, highly flawed formula. Putting thousands (perhaps millions) into unnecessary fear. Of course many, many of those labelled CKD (early stages) really are. It is a difficult situation as to how to distinguish those who have kidney problems, and get them proper care, from all those that are incorrectly labelled.
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