During the application process or job interview, can an employer ask about my health?
No. The Americans with Disabilities Act (ADA) strictly limits what can be asked during an interview. According to federal law, an employer can’t ask if you have a disability (such as hepatitis B) or require you to undergo a medical exam before offering you a job.
They CAN ask if you can perform the job (can you lift 50 pounds if you’re applying for a warehouse job) or how you would perform a job, but they can’t ask about your health.
Can an employer require a medical exam or ask medical questions after an offer is made?
Yes. After the offer is made, employers can require you to answer certain medical questions (such as immunization coverage) and undergo a medical exam—as long as everyone who performs that job has to undergo the same exam.
If the medical exam reveals a disability that prevents you from doing the job, even after a “reasonable accommodation” is made, then the employer can withdraw the job offer.
Can an employer withdraw a job offer after they learn I have hepatitis B?
No, because the majority of people with hepatitis B are healthy, productive and able to perform their jobs. Unless you have severe liver disease, hepatitis B does not impair your ability to be a teacher, nurse, doctor or home health aide.
If your hepatitis B status is made known as a result of a blood test or exam, that information should go no farther than the human resources department. Federal law requires employers to keep all medical records and information confidential and in separate files.
Read more at: Do You Have to Tell Your Employer About Your Hepatitis B? - Hepatitis B Foundation
Here's another thread regarding this topic: Hepatitis B and Employment