Patent ID: 7776219

Claim:
A method for filtering blood, comprising: providing an extracorporeal blood filter, the filter comprising a housing having an interior volume separated by filter media into a non-blood part and blood part; the housing including a cap that defines a headspace, between the filter media and the cap, in fluid communication with the blood part; the cap having a blood port configured for attachment to external tubing for blood supply between the extracorporeal blood filter and an external blood supply line and a dilution fluid port, through which dilution fluid flows, opening directly to the headspace such that these ports are connected only through the headspace; and at least one port connected to the non-blood part; flowing blood through the blood part while simultaneously flowing blood in the headspace, flowing blood through the blood port, and flowing dilution fluid through the dilution fluid port into the headspace, such that dilution fluid is mixed with blood in the headspace.