Every line on a medical bill carries a five-digit number, and that number is private property. A price transparency group has now asked a federal court to change that, suing the American Medical Association over its copyright in the Current Procedural Terminology system, which federal law requires providers and insurers to use.

PatientRightsAdvocate.org filed the complaint in the U.S. District Court for the Northern District of Illinois. The group is not seeking damages. It has bought a copy of the current codebook and is asking a judge to declare that scanning it and publishing it online in a free, searchable format would not infringe an enforceable copyright.

The stakes are larger than a codebook. CPT codes determine how physicians are paid, what insurers reimburse, and what patients see itemized on a bill. Members of the public who want to read the definitions must pay the AMA $137.89 for a physical copy, and organizations that use the codes in software and products pay licensing fees on top of that.

The Codes Behind Every Line on a Medical Bill

CPT is the classification system for medical procedures and services, first developed by the AMA in the 1960s and revised annually. Federal law requires providers, insurers, and physicians to use the codes in electronic billing, and federal law, along with at least 45 states, requires their use in connection with Medicare, Medicaid, and other government programs.

That gives the codes an unusual status. They function as regulatory infrastructure while remaining, in the AMA’s position, the association’s private intellectual property. The organization licenses the set, and the revenue from that licensing has long been a significant part of its finances.

For a patient, the consequence is concrete. Someone comparing what a procedure should cost, or checking whether a bill matches the care they received, is working with numbers whose official definitions sit behind a paywall. Free lookup tools exist, and Medicare publishes payment amounts for many services, but the authoritative descriptions are licensed.

The group framed this as the core grievance in its announcement, arguing that the association “has no valid copyright in CPT” and should not charge the public for access. The AMA’s position is that the licensing revenue funds the expert panels and annual revision cycle that keep the code set current as medicine changes, which is not a trivial undertaking.

The complaint rests on a doctrine familiar in copyright law. Because federal and state law incorporate CPT by reference, the group argues, the codes have effectively become part of the law itself and cannot be privately owned, citing precedent holding that no one can own the law. As an alternative, it argues that free nonprofit publication would qualify as fair use.

The filing also revives an older finding. A federal appeals court held in 1997 that the AMA misused its CPT copyright through an arrangement under which the federal government adopted the system while agreeing not to use a competing coding standard. The group argues the effects of that arrangement remain embedded in how the system operates.

The AMA has said it will defend its intellectual property rights, framing the licensing structure as what sustains the maintenance and annual revision physicians and patients rely on. The suit follows a public letter from Senator Bill Cassidy accusing the association of charging excessive fees for a government-backed monopoly.

Whether the group succeeds turns on a question courts have not squarely resolved for this system: whether a code set mandated by government law can still be held as private property.

A Federal Agency Has Started Asking the Same Question

The suit lands at a moment when the government itself has opened the issue. In its proposed physician payment rule for 2027, the Centers for Medicare and Medicaid Services sought public comment on the harms and challenges tied to the AMA’s control of CPT licenses, on possible alternatives to CPT as the national coding standard for physician services, and on the implications of relying on a private organization whose decisions can influence physician payment.

That an agency is asking about alternatives at the same time a court is asked about ownership makes this more consequential than a routine licensing dispute. Neither track moves quickly. Comment periods close, rules are finalized months later, and litigation of this kind commonly runs for years through appeals. Nothing changes for a patient this year.

The Practical Stake for Someone Reading a Bill

If the codes became freely available, the immediate effect would be on transparency tools rather than on prices. Researchers, journalists, price comparison services, and patient advocates could build and publish lookup tools without licensing costs, which tends to make comparison easier and errors more visible. It would not, by itself, lower any bill. Prices are set by negotiated rates and fee schedules, not by the code definitions, and a more readable bill is not automatically a cheaper one.

What patients can do now does not depend on the outcome. Anyone can request an itemized bill listing every code charged, which providers are generally required to supply on request. Comparing that list against the care actually received is how billing errors surface, and errors are common enough to be worth the effort. Hospitals are required to post standard charges publicly, and Medicare publishes payment amounts for many services. Questioning a specific code with a provider’s billing office, in writing, is the ordinary first step before escalating to an insurer appeal or a state consumer assistance program.

Key Questions Answered

What are CPT codes? The five-digit codes that classify medical procedures and services for billing. Federal law requires their use in electronic billing, and federal law, plus at least 45 states, requires them for Medicare, Medicaid, and other programs.

Who is suing and what do they want? PatientRightsAdvocate.org filed suit in federal court in Illinois. It wants a declaration that it may scan and publish the codebook online for free, rather than damages.

What does access cost now? A physical copy is $137.89 for the public. Organizations that use the codes in software and products pay licensing fees.

What is the legal argument? Because federal and state law incorporate CPT by reference, the codes have effectively become law, and established precedent holds that no one can own the law. Fair use is argued in the alternative.

How has the AMA responded? The association has said it will defend its intellectual property rights, describing licensing as what supports the system’s maintenance and annual revision.

Would free codes make my care cheaper? Not directly. Prices are based on negotiated rates and fee schedules. Free codes would mainly make comparison tools and billing errors easier to see.

What can I do about my own bill now? Request an itemized bill listing every code charged, compare it against the care you received, and raise specific discrepancies in writing with the billing office.