Urine Drug Screens

We are planning to implement POC urine drug screens in provider offices. We are uncertain how to ensure the temperature and adulteration strips are read at the correct times. For example, our product instructions say to read some results immediately, some at 30 seconds and some at 45 seconds. The staff are not standing outside the door with a timer. Can anyone share with me how you are meeting the timing to read these results? Any other helpful tips or problems to avoid? Thanks.