I saw my nephro yesterday and asked for a cystatin C test. Now I've got two eGFRs. One is 25 and one is 36. Which is most accurate? All the articles I've found go over my head. I found one that said the margin of error for both tests was high. My eGFR based on creatinine rose from my low of 5 to steadily around 20 over the past year. Because the cause of my CKD is unusual, dehydration from ileostomy, there aren't data points to gauge my prognosis. I have my fistula and Dr. thought I'd be on dialysis by now. My Dr. said that cystatin C is more useful for people in stage 1 or 2 since the creatinine based eGFR scales for normal and CKD overlap so much. I worked so hard to get on the transplant list and they will probably make me inactive now. I know I should be happy my eGFR has gone up. The lack of any prognosis is frustrating. In the meantime I'm so tired and so cold all the time. I'm also emotionally drained. I'm so sick of going to the Y for two hours a night to try to lose weight. I'm sick of only eating one meal a day. I know if I stop doing those things I'll gain weight and get booted of the transplant list. Transplant is my best option to continue working and continue to provide health insurance for my family. I'm so sick and tired of being sick. I'm 59 and have been sick for over 44 years.
Creatinine vs. CystatinC eGFR: I saw my... - Kidney Disease
Creatinine vs. CystatinC eGFR
Bloody hell. Your post made me sad. Your post made me ask myself why I feel so sorry for myself to the extent I do. Your post made me hope to God you have hope in God - there literally isn't anywhere else to go when you're at the bottom of the barrel (I found) and how you manage not to reside there under that load...
I gather the cystatin is more accurate, but that its accuracy is useful at early stage to discern kidney problem or no. Quite what to make of you in your situation is a question I'll ask my nephr now that I figure to ask for a cystatin myself (currently eGFR 28 on creatinine)
God bless..
Thanks. Don't be sad. I had ulcerative colitis for 15 years and have had my ileostomy for nearly 30. It's ok, it's just life. Despite being ill I went to college, have worked full time or more than full time since I started baby sitting at 9. I married and have a wonderful husband and 22 year old child. Lots have it worse. I have always had to work. Since I'm a knowledge worker I can't get approved for disability. I'd have to quit my job, go without income and health insurance for my family to even apply for disability. As it stands I need to work 11 more years. My child has 4 more years under my health insurance and my husband has 11. He is 6 year younger than me. I can't imagine it given how tired I am. I feel lucky to have health insurance, so many in the US don't. I also feel lucky to live in a city with LOTS of medical specialists. I'm in the Twin Cities, Minnesota. It is a major medical hub - not including the Mayo Clinic which is an hour or so away. There are 4 transplant programs in the state and one accepted me! Many people don't have that opportunity. Thanks for your good thoughts.
Bless you for your resilience and positivity. You set a standard for most of us. Thanks for sharing your life's experiences. Praying you get the medical interventions that you need to continue your journey.
I can't answer your question, but I certainly do admire you for your positive outlook with all you've been through.
I hope you stay on the transplant list and get a new kidney soon. That would vastly improve your life and give you back your energy.
Best wishes to you, Barbara.
It was kind of a sigh for mankind. What it is people have to bear. If I was one more able to tear, I'd cry my eyes out
I've gotten off relatively lightly - 58 and only only now yanks the healthrope. I know we can "knuckle down" as you do. But as you say yourself, it is an ask, this knuckling down.
HI Barbara,The answer is not clear to any of us. My nephrologist is now running both. She said for me, the Cystatin was more accurate but for my husband, it was off. I am not sure why, but she said it had to do with body mass and fat. Here's the thing to remember. If your level is above 20, good for you. At 25 and especially at 36, you are above the level of needing a transplant. I am soooo confused why you are not doing a happy dance. You can maintain that level forever, and not do dialysis, why would you not be thrilled?
My suggestion is to speak with your transplant coordinator and get a real understanding of your situation. Since you were down to 5 at one point, I doubt they are going to throw you off the list based on one set of labs.
And I really understand and have so much compassion for what you are going through with the weight deal. I am currently fighting by transplant team for the blatant discrimination of people of size and cutting them off because they are their predetermined BMI level. So absolutely wrong. BMI is not a true indicator of body mass, and it certainly is not representative of a person's wellness. But there we are and so, I too go to the pool and work out and do everything I can to lose weight.
As far as being cold, that often indicates anemia. Aks your doctor about your hemoglobin and blood levels to see if you are anemic. It can be fixed so talk with them. Also check you PTH levels and VIT D. Those all have an impact on your wellness, feeling good about yourself and temperature.
With you in this fight so hang in there.
Thanks. Yep, I'm anemic and take iron twice a day. My PTH is stable and I'm on activated D. Overall I have a very slow metabolism. At 59 and with all my health conditions there is no magic want to speed up my metabolism. I am happy my eGFR went up, but we don't know why or for how long. After all my health problems over the years it's difficult not to constantly feel like my on eggshells and waiting for the other shoe to drop. Love my boomer sayings? I'm not even 60 until November
My goodness. I am so sorry to hear of your struggle. I do hope that the scientists come up with something that can help you soon.
Ok, my friend...Your Doctor was wrong!!! I hear your frustration. From what I read regarding the Cystatin C test, when done with those lower GFR numbers, the ones in the low 30-20s, you are likely between 25 and 36. Around 30. Now with that said, I commend you for trying to lose weight. However, eating one meal a day and working out for 2 hours is draining. Also draining will be food that you put in, like meat products that when broken down, cause your kidneys to work harder and cause inflammation. Make sure you are eating plenty of fruits and veggies. I do not eat meat. I might on a rare occasion put a piece into my mouth, but it is never a full meal. or a sandwich. Also, you do not have to work out for two hours. Just being physically active, like gardening and walking is working out. I found out the hard way regarding that. I was doing the treadmill and lifting weights and running myself ragged and ended up in the ER. So the moral of the story is, just move, eat clean foods and take some fiber supplements. Some people are gun-ho on water, but if you are eating fruit and veggie, tanking up on water is not necessary. You heal over time. You have to heal your mind, then your body will follow. So SLOW DOWN === 30 minutes at the gym is plenty. They say losing weight is 70 percent of what you put into your mouth and 30 percent exercise. I have found that it is more like 80/20. Stress is the number one killer, so you have to step back and reset your mind. Look at it like this: There are different styles of fighting. You have been punching and swinging. Well, Yoda here is now telling you to take a more Zen approach. You get up every morning and say, "Not today, Devil, Not today." Then you start taking walks and doing activities that you enjoy and live life. Reset. What you are doing now, if obviously NOT working, so pick another path.
Thanks. Sadly I can't do veggies due to my ileostomy and parastomal hernia. I ate and apple once and ended up in ER with a blockage. So I do what I can. The orders from the transplant program were to "get stronger" and "lose weight." Since I feel I have no control over food choices I do have control over going to the Y. I can't do high impact stuff, so my 2 hours is probably = to someone else's 30 minutes! We have no sidewalks in my neighborhood so walking isn't easy. I do skip the Y on the weekends and try to mall walk instead.
All the love and prayers to you.
I’m so sorry you’re going through so much. We care and are here for you. There is so much knowledge and kindness on this site. They have really done a lot of research. You came to a great forum. We will keep you in our prayers. 🙏🏻🙏🏻🙏🏻
Thanks
I'm not sure if the cystine c would be accurate for me as I'm 4'9" and 92 lbs. Using the new CKD-EPI calculator and adjusting for body surface my eGFR is 17. I have an appt with my neph on Sept and will have him do a cystine c test. I have my first appt with the transplant center on Sept 19 and know they'll take lots of bloods but not sure if they'll do cystine c or not.
Here is the correct way to use your new readings. This is from the US NIH or the equivalent of the British NHS. Since August 2021 the only recommended way to properly calculate eGFR is using Cystine-C because creatinine is so unreliable in calculating an already horribly imprecise lab measurement of eGFR.
Serum creatinine may be increased or decreased due to changes in muscle mass rather than changes in kidney function. In these situations, the serum creatinine may over or underestimate kidney function. Estimating equations utilizing serum creatinine include variables which are related to muscle mass (age, gender, and race) and may provide a more accurate indication of kidney function.3. How is a GFR estimating equation developed?Estimating equations are developed from study populations in which a measured GFR has been obtained. Through regression analysis, equations are developed which provide an estimate of GFR utilizing patient characteristics (e.g. serum creatinine, age, gender, and race) which are routinely available. Thus, estimating equations are developed in populations and may be most useful in describing risk in populations of patients. The estimated GFR will be less accurate for individual patients who have characteristics, especially muscle mass, that are different from the average in the population used to develop an estimating equation.4. Why is there more than one GFR estimating equation?There are several GFR estimating equations currently used to assess kidney function, and each equation has been developed in different study populations. Estimating equations change over time; as new equations are developed and validated in larger populations, older ones become obsolete. For example, the MDRD Study equation has been validated in CKD patients with lower levels of GFR who were predominantly Caucasian, non-diabetic, and did not have a kidney transplant. The MDRD equation has not been validated in children less than 18 years of age, pregnant women, the elderly above the age of 85, or in some racial or ethnic subgroups such as Hispanics. The CKD-EPI equation has been validated in a broader group of persons consisting of predominately Caucasians and Blacks with and without kidney diseases, diabetes, and solid organ transplants who had a wide range of GFR and ages. As a result, CKD-EPI appears to offer some improvement for eGFR between 60 and 120 mL/min/1.73 m2.5. How do we measure the performance of a GFR estimating equation?Estimating equations reflect the best estimate for the population in which they were developed. However, there can be significant imprecision when using the equation when assessing an individual. The conventional measure of precision has been the P30, which describes the percent of GFR estimates that are within 30% of the measured GFR. Measures of P30 using the same equations vary in different studies depending on the age, muscle mass, and amount of kidney disease prevalent in different population groups that have been investigated.6. Are certain equations better for estimating GFR in certain situations?GFR estimating equations are derived from and validated in studies in specific populations and include multiple variables, so it’s important to recognize that a particular equation will be best suited for use with individual patients with demographic and disease conditions most similar to those of the population used to develop an equation. The MDRD Study Equation was developed in CKD patients with lower levels of GFR (mean GFR 40mL/min/1.73 m2) who were predominantly Caucasian, non-diabetic, and did not have a kidney transplant. The CKD-EPI Equation has been validated in a group of predominately Caucasians and Blacks with and without kidney disease, diabetes, and solid organ transplants who had a wide range of GFR (2 to 198 mL/min.1.73 m2) and ages (18-97 years). Neither the MDRD Study nor the CKD-EPI equations have been validated in children, pregnant women, or in some racial or ethnic subgroups. However, the CKD-EPI equation has been evaluated in a broader range of conditions than has the MDRD equation.7. Is there a role for the Cockcroft-Gault equation?Creatinine measurement has now been standardized. Unfortunately, the creatinine method used in the development of the Cockcroft-Gault equation is no longer in use and samples from the study are not available to evaluate how the results might compare to standardized creatinine values. There is no version of the Cockcroft Gault equation for use with standardized creatinine results. A large simulation study compared eGFR by MDRD Study equation and estimated creatinine clearance (eCrCl) by the Cockcroft-Gault equation calculated from standardized creatinine values to each other and to measured GFR for the purpose of drug dosing. The results suggested that, for the majority of patients and for most drugs tested that did not have narrow thresholds for toxicity, there was little difference in the drug dose that would be administered using either equation to estimate kidney function. However, for drugs with a narrow therapeutic index, the Cockcroft-Gault equation was less reliable in assessing the risk of kidney damage.8. Is there a role for collecting 24 hour urine to calculate a creatinine clearance?For most people, creatinine clearance calculated from a 24 hour urine collection does not provide a better indication of kidney function than does an estimated value of GFR. However, for people for whom serum creatinine may be increased or decreased due to changes in muscle mass rather than changes in kidney function (e.g. amputation, cachexia, body building), a calculated creatinine clearance may be helpful.9. Why don’t you endorse one equation?eGFR provides a better indication of kidney function than serum creatinine alone and NIDDK promotes routine reporting of eGFR with serum creatinine. However, estimating equations provide only an estimate of kidney function, not the actual GFR. Development of estimating equations is a dynamic field with improved versions of existing and new equations, and equations incorporating new markers (e.g. cystatin C) appearing on a constant basis.
more:
For most people, creatinine clearance calculated from a 24 hour urine collection does not provide a better indication of kidney function than does an estimated value of GFR. However, for people for whom serum creatinine may be increased or decreased due to changes in muscle mass rather than changes in kidney function (e.g. amputation, cachexia, body building), a calculated creatinine clearance may be helpful.9. Why don’t you endorse one equation?eGFR provides a better indication of kidney function than serum creatinine alone and NIDDK promotes routine reporting of eGFR with serum creatinine. However, estimating equations provide only an estimate of kidney function, not the actual GFR. Development of estimating equations is a dynamic field with improved versions of existing and new equations, and equations incorporating new markers (e.g. cystatin C) appearing on a constant basis. All estimating equations are imperfect and none offer an overwhelming advantage for all clinical situations. The goal of NIDDK’s educational effort around eGFR is to explain the routine and appropriate use of eGFR to clinicians rather than to disseminate and implement each incremental advance in estimating GFR.10. What are considered average estimated GFR (eGFR) values for adults?The table below shows population estimates for mean (average) estimated glomerular filtration rate (eGFR) by age. These means, derived from the NHANES III survey of over 10,000 individuals, demonstrate that eGFR varies across age groups and that kidney function tends to decline with age. There is no difference between races or sexes when eGFRs are expressed per meter squared body surface area.Reference Table for Population Mean eGFRs From NHANES III4Age (Years)20-29Mean eGFR*116 mL/min/1.73 m2Age (Years)30-39Mean eGFR*107 mL/min/1.73 m2Age (Years)40-49Mean eGFR*99 mL/min/1.73 m2Age (Years)50-59Mean eGFR*93 mL/min/1.73 m2Age (Years)60-69Mean eGFR*85 mL/min/1.73 m2Age (Years)70+Mean eGFR*75 mL/min/1.73 m2*In general, the NIDDK recommends laboratories report eGFR values greater than or equal to 60 as "≥ 60 mL/min/1.73 m2," not as an exact number.
NOTE:
Reasons for this recommendation are given in the Reporting GFR section of the website.
11. Can eGFRs be used in hospitalized patients?Estimated GFR derived from the MDRD Study or CKD-EPI equation can be used in patients who are in the hospital. However, it is important to pay attention to potential inaccuracies due to the non-steady state of serum creatinine, co-morbidities that cause malnutrition, and the use of medications that interfere with the measurement of serum creatinine.5
here is the reason not to report the ACTUAL eGFR again from NIDDK.gov.
Because chronic kidney disease (CKD) is poorly inferred from serum creatinine alone, NIDDK strongly encourages clinical laboratories to routinely estimate and report GFR when serum creatinine is measured for patients 18 and older, when appropriate and feasible. Routinely reporting eGFR with all serum creatinine determinations allows laboratories to help identify reduced kidney function for providers, thus facilitating the detection of CKD. Routine reporting is easier for some laboratories than it is for others. The following information will help laboratories appropriately report eGFR.Common problems. Below are considerations for addressing common issues laboratories face when reporting eGFR:Since a patient's race is often not available to laboratories, and because mixed ethnicity can make it difficult to classify a patient's race, a general recommendation is to report the eGFR values for both African Americans and non-African Americans (See Sample eGFR Reports). This practice allows the provider to estimate the appropriate value for the patient's ethnicity. When ethnicity is known, it is acceptable to report a single eGFR appropriate for the race.Comments can supplement the calculated eGFR in cases where the laboratory’s information system cannot be programmed to report estimates based on race (African American or not African American). For example, if eGFR is reported based on the non-African American equation, a comment could state “For African Americans, multiply by 1.212, for the MDRD equation, or 1.159 for the CKD-EPI equation.”Laboratories may want to restrict eGFR reporting for some patients. In cases where information systems cannot identify patients for whom reporting eGFR is inappropriate, it is suggested that laboratories report eGFR for all patients and allow the provider to determine the suitability of a result for a patient’s condition.Reporting Values ≥ 60mL/min/1.73m2. In general, NIDDK recommends reporting eGFR values greater than or equal to 60 mL/min/1.73 m2 simply as ≥ 60 mL/min/1.73 m2, and not as an exact number. For values below 60 mL/min/1.73 m2, the report should give the numerical estimate rounded to a whole number (e.g., "32 mL/min/1.73 m2").There are three reasons for this recommendation:Interlaboratory differences in calibration of creatinine assays and the imprecision of the measurements have their greatest impact in the near-normal range and, therefore, lead to greater inaccuracies for values ≥ 60 mL/min/1.73 m2.1, 2All estimating equations are less accurate for persons with normal or mildly impaired kidney function.2, 3, 4, 5, 6, 7, 8, 9, 10Quantification of eGFR values below 60 mL/min/1.73 m2 has more clinical implications for classification of kidney function than values above this level.A laboratory that reports eGFR numeric values > 60 mL/min/1.73 m2 should use the CKD-EPI equation, because the CKD-EPI equation is more accurate for values > 60 mL/min/1.73 m2than is the MDRD Study equation. However, the influence of imprecision of creatinine assays on the uncertainty of an eGFR value is greater at higher eGFR values and should be considered when determining the highest eGFR value to report.
The Cystatin C is the more accurate always no matter what stage your are in. If it comes back better than egfr your functioning better .If it comes back less than egfr your functioning worse . Pretty simple
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