As pertains to health insurance, the look-back period refers to the length of time that an insurance company may review your health history in determining if a medical claim is related to a pre-eisting medical condition. In some cases, the insurance company may be allowed to eclude from your benefits any treatment for a medical condition that eisted prior to your effective date of coverage. When they receive a claim for any plan member, they may wish to verify that the received claim is not related to a pre-eisting condition for which they are not liable for reimbursement or claims payment. However, the insurance companies are restricted by state regulations as to how far back in your medical history they may look in determining if this claim is indeed related to a pre-eisting condition. The claims review is most commonly conducted by requesting medical records from your physician or looking at your claims history through the Medical Information Bureau. Many aspects of health insurance are state regulated, including the allowable look-back periods. This can vary substantially from one state to the net and is usually defined by the class of health insurance. The most common allowable look-back period is 12 months, but can range from 0 months to no monthly restrictions. Each state will define the look-back period by health plan type, such as individual or Small Business. The look-back period permitted on group health plans is usually less than that for individual health plans. For instance, in the state of Maryland, the insurance companies can look-back only 4 months on individual plans, but are not able to look-back at all on employer-sponsored small group plans. If an individual in Maryland enrolls in an HMO plan, the 4 month look-back period is not allowed. Information pertaining to the look-back periods for each state is available in our State Health Insurance section. Other special types of health plans, such as guaranteed issue HIPAA plans, Children's Health Insurance programs and state high-risk pools may each have their unique guidelines that pertain to the allowable look-back periods under each of these plan types.