Test and Protect, the contact tracing service, will also continue to operate throughout the festive period.
Lateral flow tests and home PCR test kits can also be ordered online for home delivery over Christmas, as well as being available at local pharmacies and test sites.
Mr Yousaf said: “I would like to thank all our testing and contact tracing staff for their commitment and dedication at this challenging time which means this vital service can remain open throughout the holiday period as COVID-19 cases continue to rise.
"Testing has been at the heart of our response to this pandemic and anyone who has symptoms or is notified as a close contact by Test and Protect should isolate immediately and book a PCR test.
"The emergence of the Omicron variant means it is more vital than ever that we use every tool at our disposal to identify COVID-19 cases quickly and break off chains of transmission.
"We are urging everyone to stay at home as much as possible over the coming weeks and reduce their mixing with other households. People should take an LFD test beforehand if they are visiting friends and family, and before situations where there is a higher risk of catching or passing on the virus."
Opening hours for testing sites, including local and drive through sites, will be the following:
24 December (Christmas Eve) 8am to 6pm
25 December (Christmas Day) 10am to 2pm
26 December (Boxing Day) 10am to 2pm
27 December 8am to 6pm
28 December 8am to 6pm
29 December 8am to 6pm
30 December 8am to 6pm
31 December (New Year’s Eve) 8am to 6pm
1 January (New Year’s Day) 10am to 2pm