Define cell passage number - (Oct/08/2008 )

Anyone out there...

How do you define "passage" for non-adherent cells ?

As far as I know, the same as for adherent cells - passaging is the act of splitting or counting-and-inoculating a cell line subculture. The big difference is just that you don't have to trypsinize a suspension culture.

You know by personal experience i found that its difficult to actually keep track of passage number in suspension cells since they mostly need to be harvested once they reach 60% confluency, and also you need to keep changing media almost once in two days...besides if you notice, under fluorescent face contrast microscope they appear biphasic since they are in suspension...also unlike adherent cells, where incase there is some caontamination in the supernatant medium, it can be replaced with fresh medium in suspension cells its not possible...so the best way i keep track is with every harvest, make a cryovial and store....