Renal replacement therapy replaces all except -
Renal replacement therapy does not replace the endocrine and metabolic functions of the kidney . It maintains plasma biochemistry (uraemic toxins, electrolytes acid base) It also removes fluid from the circulation (ultrafiltration) to maintain the plasma volume. Ref Harrison20th edition pg 290
Endocrine function
Urine output
Blood biochemistry
Ultrafiltration
Kidney