Before explaining what counts as a pre-existing condition, remember that this only matters for alternative plans, such as faith-based share plans, short-term plans, and other non-MEC plans.

If you are applying for a major medical plan, then you don't need to worry about whether your condition is pre-existing, because it's covered!

The bottom line is that whether or not your condition is considered a pre-existing condition depends on your coverage. Each provider has their own definition of what qualifies as a pre-existing condition. 

In general, A pre-exisiting condition is something you have been seen by a doctor for already, anything you may be taking medication for, any change of medications in the last 6-12 months. 

Here's how Medi-Share defines pre-existing conditions, which is a good guideline for other alternative plans:

Medi-Share won’t deny you for a pre-existing condition, but there may be a “phase-in” period before you’ll get full coverage.  As an example, if you’re pregnant and then sign up for Medi-Share, it won’t be covered.

F. Pre-Existing Medical Conditions or Related Conditions

Medical bills for diagnosis or treatment of a pre-existing medical condition, defined as signs/symptoms, diagnosis, treatment, or medication for a condition prior to membership, will be eligible for sharing as follows:

High blood pressure or cholesterol that is controlled through medication or lifestyle will not be considered a pre-existing medical condition for purposes of determining eligibility for future vascular events.