Your blood sample needs to be posted in a “priority postbox” on the day it’s taken. In addition, the blood sample needs to be posted before the last collection time on that day, otherwise, it will only get to the lab the following day and will sit in a hot postbox overnight. Please look up here where the closest “priority postbox” is to you. We would usually recommend taking your “finger prick test” on a Monday to Thursday to make sure that it gets to our lab safely without delay. In the case of a bank holiday, we recommend posting your sample up until the Wednesday before the bank holiday or waiting until the following Tuesday to take your test. This prevents your sample from being delayed in the post which could affect your results.