CMS SOM App. H, Tag V359

494.50(b)(1)

11 Reprocessing

11.3.2 Ultrafiltration

If the patient’s expected weight loss is not achieved with the reprocessed dialyzer, the

reprocessing method and all other weight removal variables should be reevaluated.

Interpretive Guidance § 494.50(b)(1)

ANSI/AAMI RD47:2002/A1:2003

11.3.2 Ultrafiltration

In vitro ultrafiltration coefficients should not be used to predict in vivo results.

AAMI Rationale for the Development and Provisions of this Recommended Practice

A.11.3.2 Ultrafiltration

Ultrafiltration rate (UFR) is the flow rate of fluid that passes through the membrane under a

given pressure gradient at a given temperature. It is the product of the ultrafiltration coefficient

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of the hemodialyzer (KUF) and the transmembrane pressure. The KUF, and thus the UFR at a

given transmembrane pressure, may be affected by changes in the intrinsic permeability of the

membrane, the surface area of the membrane, and the presence of hydraulically resistive

deposits on the membrane. Cleaning agents, such as sodium hypochlorite, may affect the

intrinsic water permeability of many types of dialysis membranes.

In vitro KUF is not recommended to predict in vivo ultrafiltration performance because the

former overestimates the latter in hollow-fiber hemodialyzers. This difference occurs in part

because of the additional hydraulic resistance of the formed elements and proteins in blood.

Additional Guidance:

Assessment for compliance with this requirement should find patients are weighed before and

after each treatment. Missed weights should be rare and include an explanation for the weight

not being obtained. Repeated entries of “unable to stand” should result in a change in the plan

of care to allow determination of pre- and post-treatment weights.