1. Measurement and Estimation of Residual Kidney Function in Patients on Dialysis 
Tariq Shafi, Andrew S. Levey 
Advances in Chronic Kidney Disease 
Volume 25, Issue 1, Pages (January 2018)
DOI: /j.ackd
Copyright © 2017 National Kidney Foundation, Inc. Terms and Conditions

2. Figure 1
Total kidney function—a new conceptual framework to assess kidney replacement therapies. A conceptual framework for assessing total kidney function in patients treated with kidney replacement therapies. The total function is a sum of residual kidney function plus the function provided by kidney replacement therapies. Total small solute clearance is a component of total kidney function and is the sum of small solute clearance by glomerular filtration, tubular secretion, and kidney replacement therapy.
Advances in Chronic Kidney Disease  , DOI: ( /j.ackd )
Copyright © 2017 National Kidney Foundation, Inc. Terms and Conditions

3. Figure 2
Extrarenal clearance of iohexol. Comparison of clearance measurements in the Residual Kidney Function Study.36,37 (A) Scatterplot of 24-h plasma clearance of iohexol (CL iohexol) vs 24-h urinary CL iohexol. Dashed lines and shaded areas represent the linear fit and confidence interval of the linear regression. (B) Plot of extrarenal CL iohexol (24-h plasma CL iohexol, 24-h urinary CL iohexol) vs 24-h urinary CL iohexol. Positive numbers represent overestimation of 24-h urinary CL iohexol and negative numbers represent underestimation. Dashed line represents fit from a median quantile regression of the extrarenal CL iohexol on 24-h urinary CL iohexol. Abbreviation: RMSE, root-mean-square error.
From Shafi and colleagues, reproduced with permission.37
Advances in Chronic Kidney Disease  , DOI: ( /j.ackd )
Copyright © 2017 National Kidney Foundation, Inc. Terms and Conditions

4. Figure 3
Diagnostic accuracy for estimating CLUREA ≥2 mL/min. Receiver operating characteristic (ROC) curves for the diagnostic accuracy of estimating equations by Shafi and colleagues55 in 826 patients on dialysis of the NECOSAD. Sensitivity (%) is presented on the y-axis and 100-specificity (%) is presented on the x-axis. Solid black line was calculated using the urea and creatinine equation, solid blue line the BTP equation, solid green line the B2M equation, solid red line the cystatin C equation, and orange line the BTP + B2M equation. Abbreviations: B2M, β-2 microglobulin; BTP, β-trace protein; CLUREA, urinary urea clearance (mL/min); CLUREA, CREAT, average of urinary urea and creatinine clearance (mL/min/1.73 m2); NECOSAD, Netherlands Cooperative Study on the Adequacy of Dialysis. From Shafi and colleagues,55 modified with permission.
Advances in Chronic Kidney Disease  , DOI: ( /j.ackd )
Copyright © 2017 National Kidney Foundation, Inc. Terms and Conditions