Question: How do I code for a transgender patient receiving a screening mammogram? We have a patient listed as female on our medical records, but there’s a discrepancy with the insurance company, which lists the patient as male. The claim was denied due to gender mismatch. Oklahoma Subscriber Answer: The Centers for Medicare and Medicaid Services (CMS) cleared this up in MLN Matters® Number: MM6638. Specifically, CMS states that this MLN Matters article is “based on Change Request (CR) 6638 which provides instructions for completing Part A and Part B claims for gender specific services for beneficiaries who are transgender, hermaphrodites, or have ambiguous genitalia.” Furthermore, “CR 6638 instructs physicians and nonphysician practitioners that for Part B professional claims the KX modifier [Requirements specified in the medical policy have been met] should be billed on the detail line with any procedure code(s) that are gender specific for the affected beneficiaries.” Modifier KX is referred to by CMS as a “multipurpose informational modifier.” In addition to other uses, such as in the case of medically necessary extra hemodialysis procedures, CMS states that “the KX modifier should also be used to identify services that are gender specific (i.e., services that are considered female or male only) for effected beneficiaries on claims submitted by physicians and nonphysician practitioners to Medicare carriers and MACs.” Coder’s note: For Part B claims, you only need to append modifier KX to 77067 (Screening mammography, bilateral (2-view study of each breast), including computer-aided detection (CAD) when performed). CMS requires that Part A patients must report condition code 45 (Ambiguous Gender Category) on the inpatient or outpatient service.