Question: A patient's primary insurer is Medicare, and she also has secondary insurance. Medicare has paid its portion, and the explanation of benefits shows patient responsibility as the amount left over. Medicare did not forward to the secondary insurance. Are we responsible for filing the secondary (as the patient believes), or can we bill the patient and have her submit to her secondary? Georgia Subscriber Answer: Filing the claim on your patient's behalf might be in your practice's best interest. Many statements that patients receive from their physicians do not include all the information an insurer requires. This may slow down reimbursement if the patient tries to file the secondary claim himself. Secondary carriers will be able to pay the difference faster if they receive a CMS-1500 form. First step: Check your Medicare explanation of benefits. The EOB will show you if the claim is crossing over to the secondary carrier. Then, print out each secondary claim that you-re not sure will cross over. Next: After one month, if the secondary carrier hasn't paid the claim, either submit the claim for the patient or call the secondary company and make sure it hasn't already received the claim from Medicare.