Can my boss ask me to produce a copy of a hospital dismissal to justify my work absence?

Yes, it is legal for your boss to request documentation from the hospital that you were in the hospital. Your boss cannot request your diagnosis or other medical records, but simple proof that you had been admitted to, had spent time in, and then had been discharged from a hospital is something an employer can request, since that is evidence of the mere fact of hospitalization, not of private medical records.

There are things an employer cannot ask an employee for, such as the details of his or her diagnosis or prognosis, medical test results, or the medical treatment that he or she is undergoing. But the employer can ask for proof that you were in the hospital, as well as confirmation of the days (i.e., how long) you were hospitalized or undergoing treatment.

This may seem intrusive or unfair, but there is a valid reason. Remember: all employment in this country is “employment at will,” at least if there is no written employment contract (including a union contract or collective bargaining agreement) changing that. (If you do have a written employment contract, review it to see what, if anything, it says about this situation. If the contract covers medical absences, whatever it says about them applies and its terms must be honored.) Among other things, “employment at will” means that an employer can terminate an employee at any time, for any reason not specifically prohibited by law (such as certain forms of illegal discrimination); it also means that the employee has no right to a job—and also no right to miss work and come back to his or her job. This in turn means that an employer may terminate an employee for missing work, unless—

  1. The employee has and uses some form of paid time off, like sick leave, for the absence;
  2. The employer is covered by FMLA or a similar state leave law, the employee is eligible for that law, and the reason the employee was out falls under the law, too (more information about FMLA is on the U.S. Department of Labor's website; state leave laws can be found on your state department of labor website); or
  3. The employer otherwise allows absences for a certain reason, such as calling out sick.

The common thread with 1–3 above is that the reason you were out matters. Sick leave can only be used for illness or medical care, as can FMLA leave. If the employer allows you to otherwise miss work for certain reasons, they can make sure that that reason is what in fact occurred. And if you were out for the wrong or unapproved reason, they can terminate you.

Furthermore, the employer does not need to trust the employee or take his or her word for what happened. After all, it is very easy to lie, and claim you were in the hospital when you were on a vacation instead. So, since the reason you were out matters, and since your employer doesn’t have to take you at your word, your employer can ask for proof of the hospital stay.