Once a dialyzer is recirculating, and a patient becomes a "no-show", how long until you have to discard that dialyzer and blood tubing set? (NON-REUSE CLINIC)

Along with the time, can you explain where that time limit originates from (publication, Conditions of Coverage)

Have worked with a couple of organizations that call for a two hour protocol on discarding no-shows.

I don't understand why you would discard after only two hours... is there a rationale? The patient dialyzes for 3+ hours at a time...
We run another bag of saline through the dialyzer to wash out any leeched plasticizers (assuming heparin isn't an issue for the next patient of course). We normally won't hold it for longer than four - five hours....
Don't have a reference to cite, except this has been our practice for well over twenty years.

Our unit policy is 4 hours. If the patient calls off - we are calling another patient in early so we don't waste the entire set up.
(no reuse here - of course!)