Is the office looking a little emptier this flu season? We hope that’s because you listened to our advice for getting sick employees to stay home, but there is no denying that flu cases are on the rise across the nation. If you’re the boss, you may find yourself managing a skeleton crew of healthy employees. And that stress may leave you wanting to launch an inquisition into every sick employee. But hold on, Don Quixote—before you go tilting at windmills, let’s double-check what information bosses are allowed to get from employees who call out sick.

Employees’ medical privacy is protected by HIPAA, FMLA, ADA, and various state laws, each with its own nuances. So while it’s safe to ask for a general explanation for the absence—whether the employee is sick, the employee is caring for a sick loved one, or the employee is seriously injured—beyond that is risky, even if you’re genuinely concerned. Stick to facts that relate to the job and business necessity, such as asking when an employee expects to return to work.

If you’re concerned about abuse of sick leave, you can require a doctor’s note to return to work after an illness. (The note should verify that the employee was evaluated by a doctor and that the employee needs to use sick leave.) This requirement should be written in the employee handbook and applied consistently, such as when an employee calls out for three consecutive days. But use this route with caution! Many employees will feel mistrusted if they have to prove their illness, and employees with common illnesses will be forced to see a doctor when they otherwise wouldn’t have.

During this supercharged flu season, privacy can be the best policy when it comes to sick employees. So while it’s tempting to ask for details of an employee’s illness, even out of concern, it’s safer to say, “I hope you feel better soon” and move on. Perhaps a more fruitful question to ask: Why are you concerned your employees are abusing sick leave?