<qa>  How long should a minimum of 2 measurements of eGFR or sCr8. A minimum of 2 measurements of eGFR or sCr should be obtained at least 3 months apart prior to the Screening Visit or within the previous 18 months to define the rate of progression of CKD. The subject should have adequate, historical clinical data to provide a reasonable estimate of the rate of progression of CKD. The Medical Monitor may be consulted to ensure there is sufficient data. 