If you are considering purchasing private health insurance, you need to be well-versed in the concept of pre-existing medical conditions before you compare health insurance.

Whether a pre-existing medical condition would be covered under new medical insurance depends on several factors: what the condition is, how long you have had it, and what treatments you have had or are currently undergoing for it.

The way the insurer deals with pre-existing conditions will depend on whether they use “full medical underwriting” or “moratorium” underwriting. For plans that are fully medically underwritten, you disclose your medical history in your application, and the insurer will do one of the following: accept you without exclusions; accept you but exclude treatment for the pre-existing condition(s); reject you.

With moratorium underwriting, you won’t fill out a medical questionnaire when you apply, but the insurer will exclude any pre-existing conditions you have or have had within a period (usually five years) before joining the insurance plan. The exclusion may or may not be permanent. In general, the more costly and repeatedly a condition needs treatment, the increased likelihood that it will never be covered under private health insurance.

Make sure you disclose all pre-existing conditions when you compare health insurance. Failing to do so could result in denial of future claims or even cancellation of your policy.