Hello Everyone,
So I'm wondering if anyone can shred some light on this question.
When my labs are done at the hospital I go to my eGFR is 44. When I use the eGFR calculator from the national kidney foundation using CKD-EPI creatinine equation my eGFR it is 52 (I'm using the creatinine level from the labs taken at the hospital). Shouldn't they be the same?
GFR can fluctuate hourly as well as the lab results. Remember, it is E GFR which means estimated GFR. It is not exact science.
Thank you Bassetmommer
Mine also is different if use the new equation that considers BMI. Link to NIH article on differences in calculations. ww.niddk.nih.gov/health-information/professionals/clinical-tools-patient-management/kidney-disease/laboratory-evaluation/glomerular-filtration-rate/estimating
Hey can you resend the link, it does not work
Did they use the MDRD equation?
Hi Marvin8, It doesn’t say on the lab report but I found the MDRD equation online and YES that equation gave me an eGFR of 44. So I think your absolutely right that’s the equation they must have used. I was hoping the 50s was more accurate. I noticed on the NKF app they don’t have the MDRD formula, I wonder why. Anyways thank you Marvin
MDRD formula has been around the longest and it's the most agreed upon formula by the labs for those whose eGFR is below 60. For those whose eGFR is above 60, the ckd-epi formula is supposed to be more accurate. And the ckd-epi formula combined with the formula based upon cystatin-c is supposed to be more accurate. The question I have is whether or not the combined formula is more accurate than the MDRD if the eGFR is below 60. Seems to me that folks like myself who are in the mid-hi 50's are going to be the most uncertain. The labs simply default to formulas that are what they are.
Thank you Marvin8. I have the same question too, concerning the equation with the cystatin C and creatinine combined. My doctor is old school and only does creatinine. Maybe I just want a better eGFR too much
My nephrologist says he doesn’t pay much attention to the eGFR but rather the creatinine level and the protein in the urine, which are much more important indicators of kidney function than the GFR.
Thank you!
This is exactly what I said in one of my comments. My Neph uses creatinine and urinalysis to check kidney function. People should not get so hung up on GFR. GFR is calculated using creatinine and can vary depending on the calculation used. Both of these values are used to look at a trend over time. Knowing your GFR at any given time really doesn't tell you much except that maybe your kidneys aren't at the level they should be for your age. Also, there are outside factors that can affect kidney function on an otherwise healthy person. I'm going to use my wife as a prime example. She is 65 and has been seeing the same GP every 6 months for years and her GFR should be >60. She would do a full set of labs each time and tell me the GP said she is fine after her appointments. I started taking a look at her lab results and saw a big red flag and this is something I hear people complain about GPs is that they don't bother to mention kidney function and sometimes until it's too late. The spreadsheet I'm posting is my wife's GFR from 2019-2022. She has been in need of a hip replacement for several years but has elected to defer surgery. To help deal with the pain, she was taking lots of Ibuprofen which will definitely alter kidney function. I told her she needed to stop or at least cut back on the amount she was taking. We saw an improvement in her GFR after that but then it started going back down again. I was able to get her in to see my Neph to see if he could help. Back in 2019, she had a scare when her BP shot up really high and I took her to the ER. They gave her Hydralazine and Hydrochlorothiazide and that brought the BP down nicely and let her go home. We researched Hydralazine and found that it can cause GPA which is the autoimmune that I have and that's what destroyed my kidneys. She told her GP she was concerned and the GP blew it off and said that's so rare to not worry about it so she was on it for several years. When my Neph saw my wife's drug list, the first thing he said is I'm taking you off the Hydralazine and Hydrochlorothiazide that those are two of the worst medicines to be taking. He told us he has several patients with GPA and CKD that was caused by the Hydralazine. It took 6 to 9 months but we saw her GFR start going back up and her last labs she is at GFR of 58. You can see that at one point, she was at 39 so it is possible for GFR to fluctuate quite a bit depending on your circumstances. I will say that her diet didn't change much over this period except for cutting out carbs.
Do you know what parts of the urinalysis your doctor looks at?
I think the two most important ones are protein and blood. In my case, the GPA autoimmune that I have is a form of vasculitis and it affects small to medium blood vessels which is what damaged my kidneys. They will also look at the amount of creatinine in your urine, especially for the 24 hour urine collection. It should be the inverse of the amount they see in your blood.
Thank you LLWegeners I do have positive blood depending on the sample. I need to ask for a 24 urine because my doctor never has done that. Thanks!
Your diet is rhe main thing. Stop eating meat which is your main source of creatinine ...then watch your numbers co.e up. Also every year older will make it lower too, but nothing you can do about that.
If you want something more telling ask for a Cystatin C test. Then you will know if your lower GFR might actually be higher.
Thanks Roxanne! I really want that test. I’ve been thinking of ordering it myself online :/
Right. According to the kidney foundation, you lose 1% of your filtering starting at age 45.
You need to be careful of that. I have been trying the low protein thing due to the amount in my urine and it's caused my blood protein to get too low. Now my neph wants me to eat more protein. I also did the cutting out sodium, never added much if any, and I watch and don't eat high sodium foods and now my sodium is too low. Watch ALL of your lab results and be careful about making changes without knowing how it affect everything.
This is the one my kidney doc uses along with the body surface area checked as I'm very small. It gives me an eGFR of 17 and that is what he used to refer me to the transplant center.
I am now 90 y.o.a, Born with a Binary renal system and constant UTI's I am CKD . My last lab test reported 'Chronic cystitis - worsening. No further culture at this time.' There were also white and red cells found in the specimen. The terrible burning and discomfort remain and I am beginning to suspect that lab tests may not always be completely accurate, but that is only my thinking however and I know that test results can vary. Sorry I can't give a more definitive reply but I do sympathise with you.
Thank you wingsofadove
Creatinine vs. CystatinC eGFR
Labs
