Briefly, in our previous recently published work, we have found that in the global 300-patient GFR evaluation, CKD-EPI and Hoek equations displayed the highest statistically significant correlations and the best lineal regressions with respect to 99mTc-DTPA, and the different creatinine-based equations showed a high and significant correlation among themselves; the same phenomenon was reported with cystatin C-based formulas. This evidence concerns the gene CST3 and chronic kidney disease.