Mae dialyzer fflwcs uchel yn offeryn a ddefnyddir mewn dulliau trin puro gwaed fel hemofiltration, hemodipiltration, a hemodialysis fflwcs uchel.
Flux refers to the dialyzer's ability to remove water, expressed by the ultrafiltration coefficient Kuf (ml/mmHg/h), which means the number of milliliters of water ultrafiltered by the dialyzer per hour and per mmHg pressure. According to the Kuf value of the dialyzer, the dialyzer is divided into low-flux, medium-flux, and high-flux dialyzers. A high-flux dialyzer is defined as a dialyzer with Kuf>20-25ml/mmHg/h, deialydd fflwcs isel gyda Kuf<10ml/mmHg/h, and a medium-flux dialyzer between the two. A high-flux dialyzer can remove more medium-molecular-weight toxins than a low-flux dialyzer, and is used in blood purification treatment modes such as hemofiltration, hemodiafiltration, and high-flux hemodialysis.