Yes Hala, prior to freezing you have to count with a good method you have on hands and then you can freeze. Try to use a good protocol for freezing and use the same amount of cell per vial.

Hi,

Yes, actually it´s reccommended using the same concentration of cells per tube (10 millons per ml, for example). After counting, remember to resuspend in medium with 5-10% DMSO to prevent cell lysis after thawing. If you´re using these samples in a month lime lapse, you might considerate freezing in liquid nitrogen.

Of course, if needed, you should count again after thawing (because of cell death during the process)

Good luck!

Did you freeze the cells in RNA lysis buffer? If yes, many kits have recommendations for volume of lysis buffer to add per total cell number. As long as these guidelines were mostly followed, your sample is safe at -80.