How soon after an employee provides notice of the need for leave must an employer determine whether someone is eligible for FMLA leave?

Absent extenuating circumstances, the regulations require an employer to notify an
employee of whether the employee is eligible to take FMLA leave (and, if not, at least
one reason why the employee is ineligible) within five business days of the employee
requesting leave or the employer learning that an employee’s leave may be for a FMLAqualifying
reason.