If modifier CS (Cost-sharing waived for specified covid-19 testing-related services that result in and order for or administration of a covid-19 test …) confuses you and factors into claims denials, you’re not alone. In fact, one Medicare Administrative Contractor (MAC) recently issued fresh guidance on the proper way to use the code. Remember: Starting on March 18, 2020, the Families First Coronavirus Response Act (FFCRA) mandated that Part B practices append modifier CS to any E/M service resulting in the provider either administering or ordering a COVID-19 lab test for the patient for the duration of the PHE. “Outpatient providers, physicians and other providers and suppliers that bill Medicare for Part B services under these payment systems should use the CS modifier on applicable claim lines to identify the service as subject to the cost-sharing waiver for COVID-19 testing-related services and should not charge Medicare patients any co-insurance and/or deductible amounts for those services,” Part B MAC NGS Medicare reminds in a Nov. 4 news release. Another Part B MAC, First Coast Service Options (FCSO) agrees. “The CS modifier waives the beneficiary cost-sharing, allowing the claim to pay at 100 percent of the fee schedule amount. The CS modifier does not need to be added to lab codes,” FCSO says in online guidance. Medicare providers should also be checking the Centers for Medicare & Medicaid Services (CMS) quarterly releases of the agency’s Integrated Outpatient Code Editor (I/OCE) files, NGS urges. “The I/OCE program processes claims for all outpatient institutional providers including hospitals that are subject to the OPPS as well as hospitals that are not (Non-OPPS). Specific to the PHE, the quarterly I/OCE files identify HCPCS codes that are eligible for coinsurance and deductible,” NGS indicates. Read the NGS update at >www.ngsmedicare.com/web/ngs/news-article-details?selectedArticleId=800435&lob=96664&state=97178®ion=93623 and find the October 2021 I/OCE files, which include the most recent quarterly changes, at www.cms.gov/Medicare/Coding/OutpatientCodeEdit/OCEQtrReleaseSpecs.