Figure 3.

Comparison of the percent volume recovery from each syringe filter such as nylon, polypropylene (PP), polyvinyl difluoride (PVDF), and polytetrafluorethylene (PTFE), utilizing an artificial saliva solution (A) without and (B) with bovine serum albumin (BSA). (C) Shows the change in the concentration of pepsin after passing through a PP and PVDF filter, respectively. (D) Comparison of the concentration of pepsin in the saliva of laryngopharyngeal reflux (LPR) patients which is pre-processed with the PP filter and a centrifuge (as a standard method). The pepsin levels were measured utilizing a pepsin enzyme-linked immunosorbent assay (ELISA) assay.