What Are CMS Condition Codes and How Do They Work?

CMS condition codes are two-character identifiers placed on institutional healthcare claims to tell the payer something specific about the circumstances behind the bill. They flag situations like a patient’s status change, coordination with another insurer, or a beneficiary’s request for a formal Medicare denial. They appear on every institutional claim submitted through Medicare, Medicaid, and most commercial payers that use the UB-04 format, and getting them right decides whether a claim pays, is returned, or draws an audit.

A condition code can be letters, numbers, or a mix. It’s situational: you use it only when the specific condition actually applies to the billing period. A straightforward inpatient stay may need none at all; a complex claim involving workers’ compensation, a status change, and a demand for a formal denial may need several. These codes aren’t diagnosis codes or procedure codes. They don’t describe what’s wrong with the patient or what was done. They describe the billing situation itself so the claims processor knows what to account for before adjudicating.

Where Condition Codes Go on the Claim

On the paper UB-04 form (also called the CMS-1450), condition codes occupy Form Locators 18 through 28, giving you room for up to 11 codes per claim, entered in numerical order starting at FL 18.¹ Most claims use only one or two, so running out of space is rare.

Condition codes do not appear on the CMS-1500 form, which physicians and other noninstitutional providers use. They exist exclusively on institutional claims.

Reporting on the 837I

The electronic equivalent of the UB-04 is the 837I (Institutional) transaction. There, condition codes go in Loop 2300, within the HI segment, using qualifier “BG” to identify the entry as a condition code.² The electronic format works the same way as the paper form for adjudication; the data just sits in a different structure. If your billing software populates the UB-04 fields correctly, the 837I mapping usually handles itself, but it’s worth verifying during claim scrubbing that the HI segment actually contains the codes you intended.

The Condition Codes That Cause the Most Trouble

Hundreds of condition codes exist. A small set drives most of the questions and most of the claim problems.

Condition Code 44: Inpatient Changed to Outpatient

Probably the most scrutinized code in hospital billing. You use it when a physician ordered an inpatient admission, the hospital’s utilization review committee later determined the stay didn’t meet inpatient criteria, and that determination happened before the claim was initially submitted. The hospital then changes the patient’s status and bills the services as outpatient, placing condition code 44 on the outpatient claim (Type of Bill 13x or 85x).³ CMS uses the code for monitoring, allowing Quality Improvement Organizations to track how often hospitals reverse inpatient orders.

Condition code W2, created through the 2014 Inpatient Prospective Payment System final rule, serves a related purpose. W2 allows a hospital to self-deny an inappropriate inpatient admission after the claim has already been submitted, then rebill eligible services under Part B. The distinction: code 44 applies when the status change happens before the original claim goes out, W2 when the hospital catches the problem afterward. Both require a physician member of the utilization review committee to make the determination.

Condition Codes 20 and 21: Demand Bills and No-Pay Bills

Both codes handle situations where Medicare probably won’t pay, but the provider submits the claim anyway for a specific reason.

Condition code 20 is used for what CMS calls a “traditional demand bill.” The provider has told the beneficiary Medicare is unlikely to cover a service, but the beneficiary wants the claim submitted. Charges go on the claim as noncovered. One critical rule: condition codes 20 and 32 (which signals an Advance Beneficiary Notice was given) can never appear on the same claim. If you gave an ABN, you follow the ABN billing path, not the demand bill path.⁴

Condition code 21 produces a “no-pay bill.” The beneficiary wants a Medicare Summary Notice showing the denial, which can then be passed to a secondary payer. All charges on a condition code 21 claim must be noncovered, and an ABN is not required. If a claim with condition code 21 doesn’t conform to the formatting requirements, the Medicare Administrative Contractor returns it to the provider.⁵

Condition Code 02: Employment-Related Condition

When a patient says their medical condition resulted from their work environment or a workplace event, the provider enters condition code 02. This flags the claim for coordination of benefits with workers’ compensation or an employer’s liability insurance. It doesn’t mean the provider has verified the workers’ comp claim; it means the patient has alleged an employment connection.⁶

Condition Code 04: Information Only Bill

Providers use condition code 04 when the patient is enrolled in a Medicare Advantage plan and the bill is being sent to Original Medicare purely for informational tracking, not for payment. The claim isn’t expected to pay; it just notifies Medicare of the services furnished.⁶

Condition Code 41 and Condition Code 92

Hospitals, critical access hospitals, and community mental health centers use condition code 41 to identify claims for partial hospitalization program services. Hospitals bill these on Type of Bill 13x; community mental health centers use 76x.⁷ The newer condition code 92 identifies intensive outpatient program services, and CMS requires it on all IOP claims. Claims with condition code 92 cannot overlap with partial hospitalization claims carrying condition code 41; Medicare’s systems will return the claim if they detect an overlap.⁸

Condition Code DR: Disaster-Related Claims

DR flags claims affected by a national or regional disaster. Its use is mandatory when Medicare payment depends on a formal waiver issued by the Secretary of Health and Human Services, and CMS also reserves the right to require DR on other disaster-affected claims. In a given emergency, CMS issues a Technical Direction Letter specifying the geographic areas covered, the applicable date range, and whether DR is required or optional for that event.⁹ Providers can no longer use DR at their own discretion the way they could in earlier emergencies; CMS now controls it.

Condition Code A6: Vaccine Billing

When billing for influenza or pneumococcal vaccines and their administration, condition code A6 is required. Missing it is one of the more common claim rejections because billers don’t always associate a vaccine charge with a condition code requirement. Medicare’s systems reject the claim outright if A6 is absent when the diagnosis code indicates an immunization encounter.

D0 Through D9: Claim Change Reason Codes

This series signals that a claim is an adjustment or correction to a previously submitted bill. Each code in the D0–D9 range corresponds to a different type of change. When submitting an adjusted claim with a frequency code of 7, Q, or 8, one of these claim change reason codes must be present or the claim will reject.

How Condition Codes Differ from Other UB-04 Codes

The UB-04 uses several distinct code types, and confusing them is a reliable way to get a claim returned.

Condition codes (FL 18–28) describe a circumstance affecting the billing period. They answer what’s unusual about this claim.
Occurrence codes (FL 31–34) report a specific event paired with the exact date it happened, such as the date of an accident or the onset of symptoms. They answer when something happened.¹⁰
Value codes (FL 39–41) report dollar amounts or statistical quantities, such as amounts paid by another insurer or the patient’s estimated liability.
Revenue codes (FL 42) identify the specific type of accommodation or ancillary service being charged, such as a semi-private room or laboratory work.¹

A common mistake is treating condition codes and occurrence codes as interchangeable. If you need to report that an accident happened on a specific date, that’s an occurrence code (like code 01 for an auto accident). If you need to flag that the patient’s condition is employment-related, that’s condition code 02. The accident date goes in one place on the form; the employment flag goes in another. Mixing them up can misdirect the entire adjudication.

What Happens When You Report Them Wrong

Condition code errors don’t all produce the same result. The consequences depend on whether the code was missing, wrong, or structurally invalid.

Claim Returned to Provider

When a claim fails basic formatting requirements, the Medicare Administrative Contractor returns it to the provider (an “RTP”) without processing it. This is not a denial; it’s as if the claim was never submitted. You can correct and resubmit, but the timely filing clock keeps running, and a returned claim has no appeal rights because Medicare never made a payment determination.¹¹ Common triggers include submitting an adjustment claim (frequency code 7 or 8) without a corresponding D0–D9 claim change reason code, or submitting a condition code 21 claim with charges that don’t add up correctly.

Claim Denial

Some missing condition codes produce outright denials rather than returns. Billing a vaccine without condition code A6 when the diagnosis indicates immunization triggers a specific rejection that requires the provider to append the code and resubmit. Overlapping IOP claims (condition code 92) with partial hospitalization claims (condition code 41) will produce a denial on the conflicting claim.⁸

Beneficiary Liability

This is where condition code errors create real financial harm. When a claim is returned because the provider didn’t meet billing requirements, the beneficiary generally cannot be held liable for those services. The provider absorbs the loss.¹¹ But when a condition code 21 claim is properly submitted and denied, the beneficiary may be liable for the noncovered charges, because the point of a no-pay bill is to obtain a formal denial. The stakes depend on which code was mishandled and whether Medicare ever reached a payment determination.

Audit Exposure

Condition code 44 draws particular audit attention. CMS and Quality Improvement Organizations track how frequently hospitals reverse inpatient orders to outpatient status using code 44 as the data point.³ A hospital with unusually high rates of condition code 44 claims may face targeted review. Recovery Audit Contractors also scrutinize inpatient admissions that should have been billed as outpatient but were submitted without condition code 44 or W2, which can result in payment recoupment.

Finding the Official List and Staying Current

The authoritative source for all condition codes is the Official UB-04 Data Specifications Manual, maintained by the National Uniform Billing Committee (NUBC). The NUBC states that no other publication, government or commercial, can be considered authoritative.¹² The manual is available through the American Hospital Association as an annual subscription running July 1 through June 30, delivered as a browser-based PDF eBook.

While the NUBC establishes the codes, CMS adopts and implements them for Medicare. CMS publishes implementation instructions through the Medicare Claims Processing Manual and individual transmittals, free to access on the CMS website.⁹ When a new code takes effect or an existing code’s requirements change, CMS issues a transmittal or MLN Matters article explaining the update. Billers who rely on the NUBC manual alone without monitoring CMS transmittals will miss Medicare-specific implementation details, and vice versa. Both sources matter, and your Medicare Administrative Contractor’s own bulletins often translate CMS policy into more specific claim-rejection guidance for the providers it serves.

1
Centers for Medicare & Medicaid Services (CMS). Medicare Claims Processing Manual Chapter 25 – Completing and Processing the Form CMS-1450 Data Set
2
Centers for Medicare & Medicaid Services. CMS 837I Version 005010X223A2 Companion Guide
3
CMS Manual System. Transmittal 299 – Use of Condition Code 44, Inpatient Admission Changed to Outpatient
4
Centers for Medicare & Medicaid Services. Medicare Claims Processing Manual – Chapter 60 – Provider Billing of Noncovered Charges
5
Centers for Medicare & Medicaid Services (CMS). Clarification to Correction to Updated Instruction on Receipt and Processing of Non-Covered Charges on Other Than Part A Inpatient Claims
6
Centers for Medicare & Medicaid Services. Medicare Claims Processing Manual Transmittal 1472
7
Centers for Medicare & Medicaid Services. Medicare Claims Processing Manual – Pub 100-04
8
Centers for Medicare & Medicaid Services (CMS). MM13222 – New Condition Code 92 Billing Requirements for Intensive Outpatient Program Services
9
Centers for Medicare & Medicaid Services. Medicare Claims Processing Manual Chapter 38 – Emergency Preparedness Fee-For-Service Guidance
10
Centers for Medicare & Medicaid Services. Transmittal 1795 (Change Request 1111)
11
WPS Government Services. How to Correct a Rejected Claim
12
National Uniform Billing Committee. Welcome to the Website of the National Uniform Billing Committee