A note on Residual Kidney Function

Over the years, with the increasingly easy access to renal replacement therapies/modalities, the importance of residual kidney function has been less and less appreciated mainly if a patient is not anuric.

It should be remembered that patients who have GFR only at 4 to 5 mL/min are continuously removing large uremic toxins like beta-2 microglobulin, which will not get cleared by dialysis. Similarly, many nonurea solutes, like indoxyl sulfate, and asymmetric dimethylarginine, which are not entirely removed by dialysis, continue to get cleared by residual nephrons even when GFR is less than 1.5 mL/min.

#nephrology

References:

1. Rottembourg J. Residual renal function and recovery of renal function in patients treated by CAPD. Kidney Int Suppl 1993; 40:S106.

2. Toth-Manikowski SM, Sirich TL, Meyer TW, et al. Contribution of 'clinically negligible' residual kidney function to clearance of uremic solutes. Nephrol Dial Transplant 2020; 35:846.