GPs are to widen tests for swine flu in the three areas of Scotland worst hit by the virus.
All patients showing up with severe flu-like symptoms at surgeries in Argyll and Bute, Paisley, and the southside of Glasgow will now be checked for the virus as a matter of course.
Until now, only those with connections to other victims or who had travelled to affected areas abroad have been tested.
The change was disclosed in revised guidance issued by public health body Health Protection Scotland, which is co-ordinating national efforts to beat the bug.
A spokeswoman for Health Protection Scotland said the guidance was regularly changed to reflect the changing situation in this country.
Recent changes concerned the testing and infection-control procedures for cases of severe respiratory disease,
A further 31 people were diagnosed with swine flu in Scotland on Thursday, where the total number of cases last night stood at 119. The cases confirmed on Thursday included a 23-month-old child in Lothian.
Of the four patients who were in intensive care, the condition of the 37-year-old man at Glasgow's Victoria Infirmary has improved. He has been transferred to the hospital's high dependency unit.
In Paisley's Royal Alexandra Hospital, three patients remain in intensive care. The 45-year-old man is in a "critical but stable" condition while the 23-year-old woman is now "stable". Both are from Paisley. The remaining patient - a 38-year-old woman - is still in a "critical" condition.
Of yesterday's new cases, 21 were in the Highland health board area, mostly connected with a cluster in Dunoon.Two primary schools in Argyll, were closed because of the virus.