Medicare's Biggest Billers

Published February 2026 · 12 min read

Lab Corporations Rule Medicare

When most people think of healthcare spending, they picture hospitals and doctors. But the biggest recipients of Medicare payments are often clinical laboratories — massive corporations processing millions of tests annually.

Laboratory Corporation of America (LabCorp) and Quest Diagnostics consistently rank among the top Medicare billers, each collecting hundreds of millions annually. These aren't fraudulent charges — they reflect the sheer volume of diagnostic testing in modern medicine.

The Concentration Problem

Medicare spending is remarkably concentrated. A tiny fraction of providers account for a disproportionate share of total payments. This isn't necessarily waste — large health systems and national laboratories serve enormous patient populations. But it does raise questions about market power, pricing leverage, and whether Medicare is getting value for its money.

Top 100 Medicare Providers