I have a female patient who has been getting testosterone injections for several years. Medicare has always reimbursed. The last claim I submitted was denied with Medicare stating CO-7, "revenue/procedure code is inconsistent with patient's gender." I understand that, however, Medicare has been paying in the past. The claims have all been submitted using the same DX codes and CPT codes. Am I supposed to be using a modifier? I haven't used one in the past. Please Advise. Thank you!