In completing a questionnaire for medical underwriting, you will very likely be asked to sign a declaration acknowledging that if you fail to answer any question accurately, truthfully and completely, the insurer can void your policy and deny any claim you make under it. And that holds whether or not the condition you failed to disclose had any relationship to the emergency that was treated.
Example: Your claim for kidney stone treatment is declined because you failed to disclose a history of diabetes (even though it was well-controlled by diet and medication). Why? Because your insurer would not have offered you coverage under the conditions or at the rates it did. It might have asked for more information about your diabetes and its severity. It might have declined you totally. And so the policy becomes null and void. It’s called Non-Disclosure and the laws uphold the insurer’s right to deny such a claim.
This makes it doubly important for you to reveal not only what you know, but what you might not know that has been written into your medical record. It’s a good idea if you see your doctor frequently for a variety of conditions to have your doctor look at the medical questionnaire and the way you’ve answered it before you submit it to the insurer. It may take a little more time and it may cost you a few dollars, but in the end you will have bought a lot of security.