What is necessary to properly collect a post BUN sample?

To properly collect a post Blood Urea Nitrogen (BUN) sample, it is essential to turn the ultrafiltration (UF) off. This is because the UF process can remove a significant amount of fluid, which may alter the concentration of BUN in the blood. By stopping the UF, the fluid levels stabilize, allowing for a more accurate measurement of BUN, reflecting the patient's true renal function rather than the effects of dialysis.

Taking steps like increasing the dialysate flow rate, waiting after treatment, or administering a saline flush do not directly contribute to the accuracy and reliability of the post BUN sample. Increasing the dialysate flow rate could introduce variability during the collection process, while waiting 30 minutes after treatment or administering a saline flush may not ensure that the sample precisely reflects the metabolic state of the patient post-dialysis. Therefore, turning off the UF is the critical action for obtaining an accurate post BUN sample.