THE MODIFIED PET (4.25%)

The 4.25% PET provides information about ultrafiltration and allows assessment of free water transport (aquaporin function)^27,28
There is good correlation between respective D/P creatinine and D/P urea results obtained with either the 4.25% PET and the 2.5% PET²⁸
This PET utilizes a 4.25% dextrose solution instead of a 2.5% and is procedurally similar to the standard PET²⁸
Additional testing of peritoneal fluid and serum sodium is required
Some experts have recommended that clinicians perform the 4.25% PET instead of a 2.5% PET to guide prescriptions²⁸; however, current prescription software has not been validated for a 4.25% PET. PD ADEQUEST software will do PET simulations for tests done with fill volumes outside of 1.5L, 2.5L and 3.0L or dextrose 1.5% or 4.25%
The 4.25% PET is a useful aid in evaluation of ultrafiltration failure^27,28

Please note: It is recommended that you use 2.5% dextrose, as the software is validated with 2.5% dextrose. If at a later date you need to work a patient up for UF failure, you can perform a 4.25% PET and compare to the 2.5% PET. Data has shown that D/P creatinine with 2.5% correlates with 4.25% PET. There is an expected difference in drain volumes between the two tests.