Referrals are an important part of a HMO (Health Maintenance Organization). In many HMO’s you need to get a referral before you can get medical care from anyone except your primary care doctor. An insurance referral is a written order from your primary care doctor for you to see a specialist. If you don’t get a referral first, the plan may not pay for the services. Check with your health insurance plan to see if you need a written referral to see a specialist. For example, the new health plans for University of Colorado Health now requires a referral to see a specialist if you have the CU Exclusive Plan. Always check with your insurance carrier if you have any questions.