For Short Term: the test officially stops when the radon sampler is sealed in the return mailer envelope (along with your info sheet). Please be sure to seal the kit completely, using tape if necessary. Short Term tests should run for at least 48 hours (2 days) and no more than 168 hours (7 days). Tests exposed for longer than 168 hours or less than 48 hours are invalid.
For Long Term (Alpha Track): the test officially stops when the test device is sealed in the return mailer envelope. Please be sure to seal the kit completely, using tape if necessary. Long Term tests should run for at least 91 days and no more than 365 days (1 year).
You can view the full instructions for your specific kit by clicking here.