SB1664, the "Honest Billing Act," mandates that off‑campus outpatient departments obtain and use unique National Provider Identifiers (NPIs) that are distinct from a hospital's main campus NPI. The bill ties reimbursement and patient liability to the use of those separate NPIs and prescribes claim form standards and an effective date for covered claims.
The measure creates multiple enforcement paths: it bars providers from holding patients financially responsible when billing rules are violated (triggering Missouri's merchandising practices law for such violations), makes proper NPI registration a licensure condition, authorizes administrative penalties and license actions by the Department of Health and Senior Services (DHSS), and allows the Attorney General and Department of Commerce and Insurance (DCI) to play enforcement and rulemaking roles. Compliance will require operational, billing, and IT adjustments for facilities that operate off‑campus outpatient sites.
At a Glance
What It Does
The bill requires each off‑campus outpatient department to obtain and use a unique NPI separate from the hospital main campus and other off‑campus locations. It conditions reimbursement on use of that NPI and specific claim formats (CMS 1500 or HIPAA X12 837P), and applies to claims filed after December 31, 2026.
Who It Affects
Hospitals and their off‑campus outpatient departments, third‑party billing vendors, health carriers operating in Missouri, and patients enrolled with those carriers are directly affected. State regulators (DHSS, DCI, and the Attorney General) gain enforcement authority.
Why It Matters
Payors and providers will need to change billing workflows and claims‑processing rules to avoid denials and patient balance‑billing disputes. The licensure‑and‑penalty framework creates a compliance lever beyond ordinary contract disputes, so hospital operator compliance programs and payer adjudication systems will need updates before the statute's effective claims date.
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What This Bill Actually Does
The Honest Billing Act creates a clear attribution rule for outpatient care delivered at locations that are owned, controlled, or affiliated with a hospital but sit off the hospital’s main campus. It borrows the federal definition of "campus" and then defines an "off‑campus outpatient department" by four elements: ownership/affiliation, distance (more than 250 yards from the main campus), organizational and functional integration with the hospital, and the provision of outpatient services.
That definitional framework is the legal trigger for the rest of the obligations.
For every off‑campus outpatient department a facility must apply for and use an NPI that is distinct from the hospital’s main campus and from other off‑campus NPIs. The bill makes two operational limits explicit: providers must file claims for services at those locations using the site‑specific NPI, and they must use standard claim vehicles—CMS 1500 forms or HIPAA X12 837P electronic transactions (or successors).
If a claim is not billed in that manner, payors may deny payment, and providers may not bill or hold the patient responsible for the charges.Missouri builds multiple enforcement channels into the statute. A facility that violates the billing rules creates a private‑law consequence: the patient cannot be held liable, and the act of misbilling is treated as a violation of the Missouri Merchandising Practices Act, enforceable by the Attorney General.
At the administrative level, DHSS may impose civil fines ($1,000 per violation), recover investigative costs, suspend or revoke licenses, place conditions on or put licensees on probation, refer providers for other investigations, and require public website disclosure of penalties. The director of DCI may refer violations to DHSS and promulgate implementation rules, but the bill contains a nonseverability clause tying those rules to chapter 536 review authority.Practically speaking, hospitals will need an inventory of outpatient sites, gap‑analysis between current claim‑submission NPIs and the new site‑by‑site requirements, and updates to billing software and payer rosters.
Carriers will need to adjust claims adjudication logic to look for site NPIs and determine whether to deny or pend claims that do not meet the CMS 1500 / 837P + site‑NPI combination. The statute's effective claims date—any claim submitted after December 31, 2026—gives a defined but tight runway for these operational changes.
The Five Things You Need to Know
The law applies to claims submitted after December 31, 2026; claims filed earlier are outside its scope.
Each off‑campus outpatient department must obtain and use an NPI distinct from the hospital's main campus and other off‑campus locations.
Providers must bill services at those off‑campus departments using the department's unique NPI and on a CMS 1500 form or HIPAA X12 837P transaction (or successor); payors may deny reimbursement if those rules are not followed.
If a facility misbills or fails to use the correct site NPI, it cannot hold the enrollee liable — such conduct can be enforced under the Missouri Merchandising Practices Act by the Attorney General.
DHSS can impose an administrative fine of $1,000 per violation, recover investigative costs, take licensing actions, require website postings, and DCI has rulemaking and referral authority subject to chapter 536 review.
Section-by-Section Breakdown
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Establishes key terms and anchors federal references
This section imports federal language for "campus" (42 CFR 413.65(a)) and borrows several terms from existing Missouri statutes to ensure consistency ("enrollee," "facility," "health carrier," etc.). For implementers, that means the bill's scope ties directly to existing federal and state definitions used by payors and licensing systems, reducing ambiguity about which locations qualify as off‑campus outpatient departments.
Targets licensed facilities and in‑state carriers; sets claims effective date
The statute applies to all licensed facilities operating in Missouri and to health carriers doing business in the state, but only for claims submitted after December 31, 2026. That carve‑in means facilities with multi‑state operations will need state‑specific billing rules for Missouri claims while preserving existing workflows elsewhere until they change.
Mandates distinct NPIs for each off‑campus outpatient department
Facilities must apply for, obtain, and use unique NPIs for each off‑campus outpatient department; those NPIs must be different from the main campus and other off‑campus NPIs. Operationally, this creates a one‑to‑one mapping requirement between physical outpatient sites (that meet the four‑part definition) and NPIs in provider enrollment files and EMR/billing systems.
Conditions payment and patient liability on correct site billing
Providers (or billing agents) must submit claims for services at off‑campus departments using the proper site NPI and a CMS 1500 or HIPAA X12 837P transaction. Payors are not required to reimburse claims that fail to meet these form and identifier requirements. The practical implication is that a claim denial could be technical (wrong NPI or form) rather than clinical, shifting the work to billing teams and payor adjudication logic.
Prevents balance billing when providers violate the statute and creates AG enforcement path
If a provider does not comply with the statute's billing requirements, it cannot collect from the patient; that misbilling is a violation of the Missouri Merchandising Practices Act. This provision gives the Attorney General a consumer protection tool to pursue systemic violations and creates a direct shield for patients facing surprise or improper bills.
Makes NPI registration a condition of facility licensure and renewal
Facilities seeking initial licensure or renewal must demonstrate they have obtained the required NPI(s) and must use those NPIs on every applicable claim. Tying NPI compliance to licensing gives DHSS a forward‑looking compliance checkpoint and creates immediate practical consequences for habitual noncompliance.
Authorizes penalties, interagency referrals, and conditional rulemaking
DHSS may assess fines ($1,000 per violation), recover investigative costs, suspend or revoke licenses, impose conditions or probation, refer matters to the Attorney General, and require public website disclosures. DCI can refer violations to DHSS and promulgate implementing rules subject to chapter 536; the bill includes a nonseverability clause that invalidates delegated rules if chapter 536 review powers are later curtailed. That clause raises the stakes for rule drafting and administrative review.
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Explore Healthcare in Codify Search →Who Benefits and Who Bears the Cost
Every bill creates winners and losers. Here's who stands to gain and who bears the cost.
Who Benefits
- Patients enrolled with Missouri health carriers — they cannot be held liable when a facility fails to bill correctly for services at off‑campus outpatient locations, reducing surprise or improper balance billing.
- Health carriers — clearer site identification on claims should improve payor adjudication accuracy and reduce disputes about where a service originated, aiding fraud detection and payment integrity.
- State regulators and consumer protection offices — the bill gives DHSS and the Attorney General explicit tools (licensure conditions, fines, MPA enforcement) to pursue noncompliant providers and protect consumers.
Who Bears the Cost
- Hospitals and health systems with off‑campus outpatient sites — they must apply for new NPIs, update provider enrollment records, reconfigure billing systems and clearinghouse mappings, and retrain staff, creating administrative and IT costs.
- Third‑party billing vendors and EMR vendors — these vendors must implement per‑site NPI support, ensure claims transmit the correct identifiers and transaction types, and may face increased support burdens for client implementations.
- Small or rural facilities that are functionally integrated with hospitals — compliance tasks and potential licensing risk may disproportionately strain small operators that rely on centralized billing and limited administrative staff.
Key Issues
The Core Tension
The bill pits patient protection and billing transparency against operational complexity and payment risk: requiring site‑specific NPIs reduces the chance a patient is unexpectedly billed for hospital rates, but it forces providers, payors, and vendors to rewire enrollment and claims systems — a process that may increase denials, administrative cost, and short‑term payment disruption even as it prevents certain types of improper billing.
The statute solves a transparency problem by tying payment and patient liability to site‑specific NPIs, but it does so by creating a new operational taxonomy that will interact imperfectly with existing federal and commercial billing systems. The bill references federal definitions (42 CFR 413.65(a)) and the federal NPI framework, yet it imposes a state‑level identifier granularity that may not align with how payors or clearinghouses currently map provider NPIs to locations.
Those mapping gaps could produce a spike in technical denials, temporary cash‑flow issues for providers, and increased administrative appeals workload for payors.
Enforcement design raises practical questions. The merchant practices enforcement mechanism protects patients but may generate litigation over whether a particular site meets the four‑part statutory definition of "off‑campus outpatient department." DHSS's broad licensure remedies and per‑violation fines create strong compliance incentives, but the nonseverability clause linking rulemaking to chapter 536 review risks legal uncertainty: if administrative review authority is later constrained, implementing rules could be invalidated, leaving both regulators and providers without clear procedural guidance.
Finally, the statute places no explicit burden on carriers to notify providers of denials tied to NPI errors, so providers could face delayed knowledge of claim failures unless private contracts or customary practices fill that gap.
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