A Centers for Disease Control and Prevention (CDC) proposal to test all baby boomers for hepatitis C is expected to bring major health benefits, but it could also result in hundreds of thousands of Americans being denied health insurance coverage, msnbc.com reports.

Health insurance companies are currently free to deny coverage to people with pre-existing conditions such as hepatitis C. Starting in 2014, a clause of the Affordable Care Act (ACA) is scheduled to prevent insurers from denying coverage on that basis. But that clause may not survive a Supreme Court ruling later this month, which experts anticipate will overturn some or all of the ACA.

Three-quarters of people with hepatitis C don’t know they’re infected. Of the 3.2 million people estimated to have hep C, roughly 2 million are baby boomers. The CDC hopes that mass testing of baby boomers will result in 800,000 new patients getting treatment, potentially saving 120,000 lives.

However, according to CDC estimates, roughly one-third of those diagnosed with hepatitis C don’t have health insurance. If key clauses in the ACA are struck down and mass testing of baby boomers goes ahead, hundreds of thousands of people will discover that they have hep C and will be unable to procure health insurance to pay for treatment.

Expert advice is contradictory, as the situation pits patients’ physical health needs against their financial health. “I would never, ever tell anybody to delay getting any kind of medical exam,” said Jesse Slome, executive director of the American Association for Long-Term Care Insurance. “But you have an advantage over the insurance company if you apply for insurance before undergoing any kind of medical checkups.”