Methods, systems, and kits are provided for performing hemodialysis, hemodiafiltration, and peritoneal dialysis on a portable machine suitable for both clinical and home use. Peritoneal dialysate can be flowed into and out of the peritoneal cavity, and can also be regenerated within the system, without the need for introducing fresh dialysate. Common hardware and software can be utilized for both peritoneal dialysis and other forms of dialysis such as hemodialysis, hemofiltration, and hemodiafiltration, allowing for facile transition between different dialysis modes using the same dialysis machine.