There are important points regarding how PSL can be used:

• Employees cannot start using accrued sick days until the 90th day of employment; after that the employee can use sick days as accrued.
• Employers can limit the amount of PSL an employee can use to five days or 40 hours per year of employment, calendar year, or 12-month period. This limitation applies even when an employee, under the default accrual method, could have accrued ten days or 80 hours of PSL (or even more if the employer did not put a cap on accrual).
• PSL must be provided upon an employee's oral or written request. If the need for PSL is foreseeable, an employee must provide “reasonable” advance notice. If not, the employee must provide notice “as soon as practicable.”
• The law does not say whether you can require the employee to provide medical certification of the need for PSL (i.e., a doctor's note). The law simply says that the employee must provide reasonable advance notification. The Labor Commissioner has stated, however, that denying leave because an employee failed to provide a doctor’s note or other details about the leave may lead to a claim against the employer for violation of the law. Unless the certification is required pursuant to another leave law, there is no provision in the law allowing an employer to require certification for PSL.1