The patients on peritoneal dialysis must have their peritoneal membrane tested and classified according to the results of the Peritoneal Equilibration Transport (PET) classification. We cannot find the PET or the required 0 hr, 2 hr, and 4 hour glucose, BUN, TP sodium, or creatinine. We do find 2 hour and 4 hour. but not 0 hour. We found two different 2 and 4 hour tests for each, one with “post” in the name, stating 2 hr post, with the sample being peritoneal fluid. The other is a 2 or 4 hour test, without the designation of “post” and having the sample as dialysate. Technically, there is not a pre or post sample in the same way as hemodialysis. But the PET does have an initial fill that is not used, and then a zero hr, 2 hr and 4 hr sample removed as part of the test. So, which is the appropriate set to use and why?