The 2021-CKD-EPI equations contain only variables of age, sex and either serum creatinine or cystatin C alone, or a combination of serum creatinine and cystatin C. While the new SCr-eGFR equation without race (Table 2) was found to have sufficient accuracy for clinical practice in many circumstances, the combined SCr-Cys-eGFR equation without race (Table 3) showed a better concordance to the measured GFR and a smaller bias between race groups. The gene discussed is CST3; the disease is chronic kidney disease.