The U.S. Fair Credit Reporting Act requires that life insurance companies tell you why an "adverse decision" was made on your life insurance application (meaning why it rejected you or placed you in a higher-risk class), according to the American Council of Life Insurers.
However, insurers are not required to go into great detail on exactly what medical condition led to an adverse decision. The ACLI says that insurers do not like to "intrude" on the relationship between applicants and their physicians, and insurers do not want to be in the position of giving an applicant a detailed diagnosis of his or her condition.
If the life insurance company has acquired medical information from your doctor, you can ask your doctor for the same information, along with an explanation of your condition. If the information affecting the decision was from lab findings on exam, this information can be sent to your doctor for you to review. In some states, medical information can be sent directly to the applicant. Check with your insurance department for the exact regulation in your state.