EGFR halved from one blood test to the next - Kidney Disease

Kidney Disease

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EGFR halved from one blood test to the next

HiveMind profile image


I had to have a blood test about a week ago as a pre-op assessment. The hospital have come back and told me that there is a concerning problem with my eGFR which is reading as 34 (is that %?) and is down from 66 two weeks ago, when I had my usual blood test (I have one every month for an autoimmune condition). I am at a loss as to why this has happened. I don’t feel any different, nor do I feel ill, which I would have presumed I would do if my eGFR was that low? Am I correct in my presumption or can you have problems and not feel the effects. My kidneys are normally fine but I did have an episode in the past which saw my kidney functionality go down to 5 (I was ill and taking too much medication - once that was sorted my kidneys went back to functioning normally). Anyone able to put my mind at rest please? Just to add that I am having a new blood test tomorrow just to make sure everything is ok.

25 Replies
orangecity41 profile image
orangecity41NKF Ambassador

Suggest you look back at other eGFR test results and see if there is a continued decline, and take results and discuss with your Doctor. Here is a link to information about eGFR tests. You have reached a good forum for information and support for Chronic Kidney Disease.

Nope. There is not a slow decline. I have, as I say, my bloods taken every month so I know exactly that my eGFR was fine up until this recent blood test. Perplexing.

orangecity41 profile image
orangecity41NKF Ambassador in reply to HiveMind

Was it a different lab, could there have been a lab error, or was it a different type of eGFR test? maybe ask for another test?

It was the lab at my main hospital which is the one that all my tests are done by.

The excuse they gave me was the it could be the heat? Could that be the cause? The nurse did say that she had had a couple of blood tests come back with strange results. But if that was the case then surely every blood marker in that test would be spoilt?

orangecity41 profile image
orangecity41NKF Ambassador in reply to HiveMind

Guess is possible cause is a heat issue.

Well I guess I can only wait and see what the new blood test says. Thanks for your suggestions.

Heat can cause dehydration and dehydration can lower eGFR. My CKD is caused by constant dehydration.

Tbh I am terrible at keeping myself hydrated. I guess I need to change that. Thank you.

eGFR does fluctuate as we age and it is just a snapshot of the time of the draw. If the hospital took it again before the surgery it more than likely would be different. What has your nephrologist told you about this? In the last couple of years I've had two surgeries and in both cases the surgeon spoke in advance to my nephrologist and cardiologist. I did a couple of tests for my cardiologist, an EKG and an Echocardiogram. Both were okay and he cleared me. My nephrologist also put restrictions on the type of antibiotics I could take and also cleared me for the procedures.

There are not usually obvious symptoms for the earlier stages of CKD. I was diagnosed over four years ago with a GFR of 32 and had no symptoms. I went back and collected hard copies of my labs and discovered that I had CKD for a year before I was told. No contrast dyes, no NSAIDs and speak or have your surgeon contact your nephrologist about the other meds to be utilized during and after the procedure.

As to your recent drop of GFR that you attributed to too many meds, it could also be just too much of one particular med. I'd suggest you use and use their MY MED LIST feature and enter all of your meds. When you do that you'll get a list of all interactions with other meds, food interactions and which meds can do damage to your kidneys.

Best of luck.

HiveMind profile image
HiveMind in reply to

I don’t have a Nephrologist. I have all the hard copies of my blood tests (I have to keep a copy of certain blood markers for my Rheumatologist). All of my eGFR results are within normal (for me).

in reply to HiveMind

Then the choice is up to you. You can see if the hospital has a nephrologist on staff and ask for an opinion considering the drop in GFR. It's your health and your life.

HiveMind profile image
HiveMind in reply to

Oh I am well aware of that. Thank you for your advice.

Bassetmommer profile image
BassetmommerNKF Ambassador

HI HiveMind,GFR is snap shot of the day and time you had it done. Also, it is sometimes known as eGFR, which means it was an estimate. So, have another draw in a week of so and see where it lands. Keep very hydrated the day before and do not do any strenuous exercise or get sweaty the day before also. Make sure you have some water before the test but not a ton. The diagnosis of kidney disease comes from multiple test for the just reason that one test may be off. So before you panic, have another test and see where things land. And then let us know how you make out.

Thank you for your suggestions and support. I will indeed report back once I’ve had a new blood draw done!

Hi. Sorry to hear about this worry. My husband got to 10% function and apart from weight loss and feeling a bit tired (but we had a new baby!), we were none the wiser that his kidneys were packing up. I’m not saying this to scare you but just to respond to your part about whether you feel ill or not. You can go a long time with issues at not necessarily have symptoms. Husband had a transplant a couple of years ago and is doing better at the moment. He is always told when it is hot that this will skew his results negatively and it always does! It’s all to do with hydration. He drinks extra extra water on these hot days to try to counteract the heat. GFR can fluctuate quite a bit. If you’re under the weather, it can also take a hit. If there is a downward trajectory over a period of weeks of tests then something else could be happening but, although it’s scary, it’s better to know earlier. With my husband, it was such a shock and he was admitted straight away as it had got so serious so soon. It wasn’t picked up before then. It got down to 7% and he had dialysis. It’s better to know sooner as you have more choices. To help GFR drink lots and lots of water, avoid too much potassium and phosphates etc (look at renal friendly recipes). I hope it is just a rogue “off” test and isn’t anything more serious.

HiveMind profile image
HiveMind in reply to Pem_0904

Thank you so much for your reply. I am due another blood test today so fingers crossed it will be better. D

Pem_0904 profile image
Pem_0904 in reply to HiveMind

Have everything crossed for you.

HiveMind profile image
HiveMind in reply to Pem_0904

Thank you.

My reply to another post in another thread. Some info may not be relevant. However, if you click my first link you will get about 45 pages of explanations as to why GFR can fluctuate from hour to hour, day to day, week to week…well you get my point. If docs aren’t worried and your creatinine, blood uric nitrogen, BUN, and urine protein are fine than I’d not worry either.

I understand the concern with GFR as it is the determining factor of our levels of CKD. However, it is an estimate that can be influenced by many factors. Most reputable websites like NKF, AAKP, NIIH and most docs only look at the lab results to determine levels and treatment every 3, 6 or 12 months because of the multiple factors tht can affect GFR. Additionally there are multiple equations to calculate GFR so if bloodwork isn’t done by two different lbs using two different methods the GFR reading may very to an extreme. Here is a good overview from NIIH

If you go to and search for GFR or eGFR there are 22 pages of results explaining in detail GFR. Educate yourself and don’t let your labs scare you or rule your life. Know what they mean and how they can vary so you aren’t living in fear. No one will advocate for you better than you and the only way you can do that is to educate yourself daily. I have been stage 4 with GFRs from 13-22 since I was 29 in 1996. In December I had a GFR of 14 due to untreated HBP for six months. Once I got back in my BP meds in December and got the BP under control my GFR in March was 20 and April 22. My new VA doc panicked in December 2020 despite my warnings to him that my creatinine would be about 4 and GFR about 15. I wasn’t off by much but he immediately requested a referral to a new nephrologist and sent me a letter about CKD 5. However, I was not panicked or worried because I knew my readings would be down due to the untreated HBP. Doesn’t mean I don’t need a group of care providers and monitoring every three months. It only means I know me and my disease well enough to not panic over one test result. You can do that as well and in my opinion you need to know all you can and reinforce or learn new things daily. It is the only way to advocate for yourself in a disease that too often gets blown off by doctors until you are in stage 4 and that is too late. I wish you all the luck in the world in your journey with CKD and I understand as a newly diagnosed patient your fear. However, it is fear that leads to not seeing this as a journey and a change of lifestyle to keep yourself out of stage 5 as long as you can. So read, learn and become a knowledgeable advocate for that special patient…you! All my best!

Thank you for the information and sharing your renal journey. I have some quite serious health issues anyway so I’m quite used to advocating for myself. 😊 I’m not entirely sure what I can change about my lifestyle because I do all the ‘right’ things (because of my health issues). I had another blood draw this afternoon so I will have to wait and see how that pans out. Fingers crossed!

If it is not a mistake than the GFR issue is probably related to something that you either did or did not put in your body yourself. Don’t get cocky. You know all there is to know about CKD? I am sure you know about what health issues you have and live perfectly in relation to those issues but each new health issue will demand it’s own diet or other lifestyle modification different from any other issue so we can all be learning and adapting everyday. I know I don’t live perfectly and do not live a perfect lifestyle for all my illnesses. However, I am a work in progress. I am learning daily even though I have had HBP for 36 years, CKD for 26 Years, multi-joint osteoporosis for 25 years, gout arthritis for 22 years, elevated lipids for 20 years, high triglycerides for 19 years, and idiopathic peripheral neuropathy for 5 years.

I am glad you have mastered your lifestyle mandates. Just don’t get used to the idea that they will not change and you will NOT be perfect with nothing to change and WILL HAVE to adapt to some lifestyle changes.

Well I certainly wasn’t being ‘cocky’ but thanks for your assumption. And I also do not know everything about CKD; I don’t remember saying I did. I don’t know anything about it. That’s why I’m on here asking for help.and advice. I also never said that I was living ‘perfectly’ as you put it. I just try my best to maintain a healthy diet/lifestyle. With regards to your last paragraph: Again, you’re assuming quite a lot about what I will have to change about my lifestyle. If required I will do whatever is necessary to adapt and change. Tell me, does renal failure come with an obligatory stick up your a**? Because *some of you people really need to take it out and stop preaching and judging to individuals who only come here for some advice.

I had no intent to come across as “preachy” or as judgmental towards you or anyone. To address your question, neither the conditions of renal failure nor CKD require or “come with” a, “stick up your ass.” I simply copied and pasted a reply to another post from a week ago that contained a link to the National Institute of Health’s kidney site, the appendix that contains several pages explaining why GFR can fluctuate frequently and quite a lot. I mentioned in my lead paragraph that the post may contain information that is not relevant to you but the link I believe is very helpful to folks looking for detailed scientific information about GFR and eGFR.

Your subsequent reply to me was you were already a great advocate for yourself (some of the information I pointed out that would not be relevant to you) and that is awesome. No one will ever advocate for those of us as patients better than we can advocate for ourselves. Additionally, you pointed out that you, “weren’t entirely sure what you could change about your lifestyle because you do all the right things now [sic]”. Again, my first paragraph explained to anyone reading that I got the rest of my reply from another post and there was probably information that was irrelevant to you or others in most of the post but the first link was what I believed to be of value.

Specific to you I never mentioned anything about self-advocacy nor lifestyle changes. Instead you assumed the entire reply was directed towards your question and it was not, I was just too lazy to retype the important information.

If you hang around long enough and can get over those of us who are “preachy” and “judgmental” you will understand that assumption is something we all must use because most people here are not doctors or medical professionals nor do many posters give a full history and lab values for us to peruse. Therefore, we have to fill in the blanks about what they are looking for in a hit and miss sort of way.

My only intent of using the specific vernacular I chose in my reply to you was to illustrate that for MOST of us as we age we will develop other illnesses or conditions that will require an adjustment in our lifestyle that we believe we are doing all the right things to address our issues. You know, just when you think you have it all figured out, BAM, life smacks you in the face with a curveball. I made the assumption it would happen to you simply based on the law of averages of lifespan and comorbid conditions that arise in a great many of us humans as we reach our eighties or nineties. I probably should not have made those assumptions and for that I apologize. Also, I apologize for any way I may have offended you or caused you to not want to return to these forums. I am just a middle-aged guy who has a little knowledge and experience in some specific health conditions who would like to help others with those conditions if possible. I am not better than anyone. In fact, I am probably low man on the totem pole around here especially.

Therefore, I do apologize for any offense or feelings of unwelcomeness. I hope you stay around and participate in the forums as I am sure we can learn from you as well. Also, I hope you keep us updated on your upcoming labs and appointments. Most of all I hope your upcoming labs and appointments indicate that your health and conditions are resolved and you are in better shape than before. I wish you all the best on your health journey and you’ll be in my thoughts and prayers regardless.

Besides being well-hydrated before the GFR test, I would also avoid eating a lot of red meat (beef, pork, lamb) right before the tests.

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