Peritoneal Equilibration Test (PET) was developed by Dr. Twardowski. Basically 2 liters of 2.5% PDF is instilled into peritoneal cavity, and the creatinine dialyzate to plasma ratio (D/P) at different time point, dialyzate glucose at different time point over the zero hour (D/Do) was measured up to 4 hours, and the ultrafiltration volume is measured at the end of 4 hours. The standard PET time points are 0, 2, 4 hours. A simplified PET only measures 0 and 4 hours. Base on the results, you may classify your patients into high (or fast), high average, low average, and low (or slow) peritoneal transport, and match the UF volume. If the UF does not match with the type of transport, there could be other causes for the UF problem.