The following checklist provides a concise list of suggestions and procedures to guide you to achieve a solid aseptic technique.  For an in-depth review of aseptic technique, refer to Culture of Animal Cells: A Manual of Basic Technique (Freshney, 2000).

Work Area
Is the cell culture hood properly set up? 
Is the cell culture hood in an area free from drafts and through traffic? 
Is the work surface uncluttered, and does it contain only items required for your experiment? 
Did you wipe the work surface with 70% ethanol before work? 
Are you routinely cleaning and sterilizing your incubators, refrigerators, freezers, and other laboratory equipment? 
Personal Hygiene
Did you wash your hands? 
Are you wearing personal protective equipment? 
If you have long hair, is it tied in the back? 
Are you using a pipettor to work with liquids? 
Reagents & Media
Have you sterilized any reagents, media, and solutions you have prepared in the laboratory using the appropriate procedure? 
Did you wipe the outside of the bottles, flasks, and plates with 70% ethanol before placing them on your work surface? 
Are all your bottles, flasks, and other containers capped when not in use? 
Are all your plates stored in sterile re-sealable bags? 
Does any of your reagents look cloudy?  Contaminated?  Do they contain floating particles? 
Do you detect a foul smell?  Unusual color?  If yes, did you decontaminate and discard those items? 
Are you working slowly and deliberately, mindful of aseptic technique? 
Did you wipe the surfaces of all the items including pipettor, bottles, and flasks with 70% ethanol before placing them in the cell culture hood? 
Are you placing the caps or covers face down on the work area? 
Are you using sterile glass pipettes or sterile disposable plastic pipettes to manipulate all liquids? 
Are you using a sterile pipette only once to avoid cross contamination? 
Are you careful not to touch the pipette tip to anything non-sterile, including the outside edge of the bottle threads? 
Did you mop up any spillage immediately, and wiped the area with 70% ethanol?