Be aware that under national laws, Medigap policies can refuse to cover your prior medical conditions for the first six months. A prior or pre-existing condition is a condition or illness you were diagnosed with or were treated for before new health care coverage began.

The wait time for coverage to start is called a pre-existing condition waiting period. You can avoid waiting periods if you buy your policy when you have a guaranteed issue right. If you buy your policy when you have a guaranteed issue right, insurers can never refuse to cover prior medical conditions coverage for any period of time.

You can also avoid or shorten a pre-existing condition waiting period if buy your policy during your open enrollment period. During this protected period, Medigap policies must shorten any pre-existing condition waiting period by the number of months you had prior creditable coverage. Most forms of health coverage count as creditable as long there was no break in coverage of more than 63 days.

Here’s how this works. If you had creditable coverage for only 2 months before you enrolled in a Medigap, a Medigap policy could only apply a 4-month, instead of 6-month,waiting period. If you had as much as 6 months prior creditable coverage, the Medigap insurers must cover your prior medical conditions immediately.

If you do not have coverage that is considered creditable, you should consider several policies. Some Medigap policies do not impose pre-existing condition waiting periods.