Wearable ultrafiltration devices methods and systems

A wearable ultrafiltration apparatus is provided. The apparatus can include a first ultrafilter for filtering a patient's blood along a first fluid path and a second ultrafilter for filtering the patient's blood along a second fluid path. The apparatus can also include a valve being positionable in a first position for directing the patient's blood along the first fluid path. The valve can also be positioned in a second position for directing the patient's blood along the second fluid path. When the valve is in the first position, blood can flow along the first fluid path and prevent blood from flowing along the second fluid path. When the valve is in the second position, blood can flow along the second fluid path and prevent blood from flowing along the first fluid path. When the valve is in the first position, the second ultrafilter can be idle and capable of being serviced or replaced and when the valve is in the second position, the first ultrafilter can be idle and capable of being serviced or replaced. Therefore, when a ultrafilter fouls, blood can be directed to the other ultrafilter while the fouled ultrafilter is being serviced or replaced.