An employer may require a proper medical certification supporting intermittent FMLA leave. That does not generally permit demanding a fresh doctor’s note for every absence already covered by a complete, sufficient certification. Initial certification, recertification, ordinary notice of an absence, and fitness-for-duty documentation are different requirements.
What the initial certification can address
The certification may establish a serious health condition, the need for intermittent leave, and the expected frequency and duration of episodes. For unpredictable conditions, a provider gives a medically informed estimate; the FMLA does not require an exact calendar of future flare-ups. A diagnosis is not invariably required. [1]
The employer generally must allow at least 15 calendar days to supply requested certification, with additional time when diligent good-faith efforts cannot meet the deadline. If the certification is incomplete or insufficient, the employer must identify the deficiency and provide the required opportunity to cure it.
When another certification may be permitted
Recertification generally follows regulatory timing limits. Longer certified durations can delay the next routine request, while six-month rules and exceptions for significant changes or doubts about validity may apply. A new leave year can also involve a new certification. An employer should identify the rule supporting the request rather than treating every absence as a new medical claim. [2]
For example, leave occurring much more frequently than the provider estimated may justify a permitted recertification inquiry. A predictable absence matching the existing certification does not automatically justify demanding an office visit merely to produce a note.
Privacy and safety boundaries
An employee need not surrender an entire medical chart. The employer may seek authorized clarification or authentication through appropriate personnel, but a direct supervisor may not contact the provider. Intermittent-leave fitness-for-duty requests have separate limits involving reasonable safety concerns. [2]
- Keep the certification, approval, and rights-and-responsibilities notice.
- Follow lawful call-in procedures for each absence.
- Ask whether a new demand is certification, recertification, or fitness for duty.
- Document any discipline tied to already approved leave.
See employer designation of qualifying FMLA leave and retaliation after FMLA if the disagreement affects attendance points, discipline, or reinstatement. Approval of intermittent leave does not excuse unrelated failures to follow lawful notice procedures.
Primary sources
Sources checked: October 31, 2026.