A dialysis module for use with a variety of single pass or single pass-recirculating artificial kidney dialyzers as desired. The apparatus has quick disconnects to allow attachment of a single pass kidney dialyzer or blocking off of a portion of a fluid conduit when a coil dialyzer is used so that a single housing can be used to provide two entirely different modes of operation as selected. A clear canister preferably forms a part of the dialysis flow path in both modes of operation to enable rapid detection of blood leaks in either mode of operation. An aspirator is associated with a recirculating pump to provide negative pressure to dialysate in the flow path when a single pass dialyzer is used while only the recirculating pump is necessary during single pass-recirculating dialysis.
