The saliva sample can be collected at any time of day. However, evidence suggests it could be better to provide a sample early in the morning rather than later in the day.1
Please ensure you do not eat, vape, smoke, drink or brush your teeth at least 1 hour before providing the saliva sample, as this can effect your results.
If you have any Covid-19 symptoms (e.g. a dry cough, high temperature, or loss of taste and smell), it is recommended that you collect the saliva sample within the first 5 days of the symptoms started from. You shed more virus particles into your saliva during this time period, making easier and more accurate to detect Covid-19 in your sample.
1. Tajima, Y., Suda, Y., & Yano, K. A case report of SARS-CoV-2 confirmed in saliva specimens up to 37 days after onset: Proposal of saliva specimens for COVID-19 diagnosis and virus monitoring. Journal of Infection and Chemotherapy (2020)