Posted on 01/31/2023 8:27:20 AM PST by ConservativeMind
A cystatin C (cys)-based European Kidney Function Consortium (EKFC) equation has similar accuracy to the creatinine (cr)-based equation for estimating glomerular filtration rate (GFR), according to a study.
Hans Pottel, Ph.D. and colleagues used data from patients in Sweden to estimate the rescaling factor for cystatin C level in adults. Rescaled serum creatinine in the EKFC eGFRcr equation was replaced with rescaled cystatin C, and the resulting EKFC eGFRcys equation was validated in cohorts of White and Black patients in Europe, the United States, and Africa.
The rescaling factor for cystatin C was estimated at 0.83 for men and women younger than 50 years of age and 0.83 + 0.005 x (age − 50) for those 50 years of age or older on the basis of data from 227,643 patients in Sweden.
The researchers found that the EKFC eGFRcys equation was unbiased, with accuracy similar to that of the EKFC eGFRcr equation in both White and Black patients, and it was found to be more accurate than the Chronic Kidney Disease Epidemiology Collaboration eGFRcys equation recommended by the Kidney Disease: Improving Global Outcomes guidelines. The accuracy of eGFR was further improved by the arithmetic mean of EKFC eGFRcr and EKFC eGFRcys compared with estimates from either biomarker equation alone.
"Improvement in estimation of the GFR was observed only in the combined EKFC eGFRcr-cys equation," the authors write.
(Excerpt) Read more at medicalxpress.com ...
I would encourage everyone to also use the adjustment option for height and weight, along with the combined use of creatinine and cystatin-C. There is no better way to estimate your true kidney function than using all these variables. For me, these jumped my eGFR up by over 30 points from just the standard creatinine formula I’d only ever used or had given to me.
My cystatin-C-only score was four points better than creatinine showed, if you were wondering about its utility. As this study shows, the combination of the two gives the best true rate approximation.
Your labs and your doctor are not likely adjusting for body surface area, weight, and the added insight of cystatin-C, so find out the truth they don’t provide using the following calculator.
https://www.kidney.org/professionals/KDOQI/gfr_calculator
Put your creatinine number in, then select “standardized assays” and “adjust for body surface area.” Even if you don't have the cystatin-C available, the body surface area will make it a lot more accurate.
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.