Ask the Expert: Don't miss Medicare sign-up deadline

If I turn 65 while I'm still working and covered through my job at a company with under 20 employees, isn't my job's insurance still my primary insurance for all doctor visits, and Medicare only primary for hospitalization? Do I apply only for Medicare Part A (hospitalization), but not Part B (doctor visits)?

No, no! You're thinking of bigger employer plans. If you're covered through a current job for a company with under 20 employees when you turn 65, Medicare becomes your primary insurance for both hospitalization and doctors' visits. Your employer plan becomes secondary — which means it stops paying for any expenses covered by Medicare.

Benefits consultants say small employers unfamiliar with the rules sometimes mistakenly assure older workers that they can stay in the company's group medical plan. In the short term, this sometimes works. But insurers routinely audit their group plans. If an audit finds you're Medicare-eligible, the insurer will send you a bill for all the claims it has paid on your behalf since you turned 65.

And that's not all. If more than three months have elapsed since your 65th birthday, your next chance to enroll in Medicare won't be until its annual General Enrollment. That takes place between Jan. 1 and March 31 for coverage starting July 1. If your employer insurance ended in April, you'll be without health insurance for 15 months. Plus, when you do get Medicare, your Part B premiums will be permanently higher.

(Other readers, please note: The above Medicare rules do not apply to people covered through a current job for an employer with 20 or more workers.)

The bottom line

To be sure you don't miss your enrollment deadline, six months before turning 65 ask your employer's insurer how your plan coordinates with Medicare.

More information

medicare.gov/node/32951

medicare.gov/sign-up-change-plans/how-do-i-get-parts-a-b/i-have-employer-coverage