2026-08-08 · 4 min
Extending sick leave (CIT) online: how to avoid a gap
When to book a CIT extension, what the doctor assesses, and why you should not leave a day between certificates.
Extending a CIT is a new medical assessment: the doctor checks whether temporary incapacity for work remains clinically justified and, if so, submits a new period to Social Security.
Book 2–3 days before the current CIT ends. Continuity matters: a day’s gap between the end of one CIT and the start of the next can be treated by Social Security as a new spell of incapacity, with an effect on benefit.
It does not have to be the same doctor who issued the first CIT. Any doctor with an active Ordem dos Médicos licence can assess and, if indicated, issue the extension, including when leave started elsewhere (health centre, hospital or A&E).
Extension is not automatic. If the doctor considers you fit to return, they may not issue a new CIT. You can seek a second opinion or go back to work; no doctor is obliged to extend without clinical indication.
For the consultation, have SNS + NISS, the end date of the current CIT and an update on symptoms. If leave does not yet exist and you only need to justify absence without benefit, also see the difference between CIT and an employer sick note.