Chargemaster review guide: CDM clean-up for hospitals

What is a chargemaster and what does it do?

A chargemaster, also called the charge description master or CDM, is the hospital's list of every individual item and service for which it has established a charge. That is the definition in 45 CFR 180.20. In practice it is the table that turns a nurse's charge entry or an order into a priced line with a revenue code and, for most outpatient items, a HCPCS code.

Three things read from the same table. The claim reads it to build UB-04 lines. The price transparency file reads it for gross charges, which 45 CFR 180.20 defines as the charge for an individual item or service as reflected on the chargemaster, absent any discounts. And Medicare bill data has to support the cost report, since chapter 25 says CMS wants providers to bill Medicare on the same basis as other payers. A mistake on one CDM line therefore repeats in all three places.

This guide covers the CDM itself: its line structure, when it must change, and how errors turn into denials. The claim path around it, from eligibility through A/R, is in the hospital revenue cycle guide. We do not repeat the stages here.

What does a chargemaster line look like?

A CDM line has an internal charge code, a description, a revenue code, a HCPCS code where one applies, optional modifiers and a price. The table shows each field and where it lands on the UB-04, using the form locators in chapter 25 of the Medicare Claims Processing Manual.

FL 45, the line item date of service, does not come from the CDM. It comes from the charge entry, and every outpatient revenue code line needs its own date. If a service is delivered 5 times in a billing period, the revenue code and HCPCS code are entered 5 times, once for each date (Medicare Claims Processing Manual, chapter 25).

The second and third lines carry the ED and observation conventions. Do not copy any of these numbers. Build lines from your own price policy.

How often should a chargemaster be reviewed?

Review the whole chargemaster at least once a year, and review the codes on it every quarter. The annual minimum comes from price transparency: 45 CFR 180.50(e) requires a hospital to update its standard charge information at least once annually. The quarterly rhythm comes from CMS itself, which publishes HCPCS files and OPPS addenda each quarter.

Drug and non-drug requests also move the HCPCS Level II code set. CMS sets the first business day of each quarter as the due date for drug and biological applications, and the first business day of January and July for other items and services. That means a new code can appear in any quarter, not just in January.

How do we handle new codes each January?

How do we map CDM lines to HCPCS and revenue codes?

Map each line in two steps: pick the revenue code that matches the department and the type of service, then add the HCPCS code the payer needs for that revenue code. CMS says the NUBC maintains the approved revenue code lists, and the Medicare contractor has the codes Medicare accepts, so check both before you build a line. Our revenue code rules page covers how each form locator is used.

Under chapter 25, FL 42 lists revenue codes in ascending order and should not repeat a code on the same bill where possible. FL 44 holds the HCPCS code for outpatient services. The Form CMS-1450 accommodates up to four modifiers of two characters each. Hospitals should not report a separate HCPCS code in place of a modifier.

Packaged items still need correct lines. Services with status indicator N are paid under OPPS but packaged into another service, and CMS asks hospitals to report packaged services and all charges because charges are used for outlier payments and rate setting. A CDM clean-up that deletes lines because they are packaged therefore removes information CMS wants.

What errors are most common in a chargemaster, and how do they cause denials?

The common errors are a missing HCPCS code, a code that does not match the bill type, a missing drug detail, a wrong unit and a stale code. Each one produces a denial or rejection that points back to the CDM, not to the claim. The table connects each error to what the remit shows.

Chart-level errors are a coding problem, not a CDM problem, and belong to billing and coding audits. The CDM errors above repeat on every claim that uses the line, which is why one wrong line can generate hundreds of denials.

Drug units are the easiest to get wrong. Medicare's rule is that units are in multiples of the HCPCS code descriptor: if the descriptor is 50 mg and 200 mg are given, units are shown as 4. When the dose is less than the descriptor amount, use 1 as the unit of measure. These come from the Medicare drug billing guidance on the revenue code 0636 page.

How does the CDM affect price transparency files?

The machine-readable file under 45 CFR part 180 lists the same codes and descriptions the chargemaster holds, so any CDM error is published. Section 180.50(b)(2) requires a general description of the item or service, any billing code with its code type, and, since January 1, 2025, any modifier that changes the standard charge with a description of how it changes it. The gross charge comes from the chargemaster.

• Update cycle. The file must be updated at least once annually (45 CFR 180.50(e)).
• Attestation. Beginning January 1, 2026 the file must carry an attestation that the information is true, accurate and complete, and the name of the hospital's CEO, president or senior official overseeing the data (180.50(a)(3)).
• Drugs. Beginning January 1, 2025 the file includes the drug unit and type of measurement (180.50(b)(2)(iii)(C)).
• Allowed amounts. Beginning January 1, 2026 the file must contain the 10th percentile, median and 90th percentile allowed amount for payer-specific charges expressed as a percentage or algorithm.

In other words, the file takes its descriptions and codes from the CDM and its allowed amounts from remittances. If the CDM maps a service to the wrong code, the file shows the wrong code next to the wrong price. Treat each CDM change as a change to the file. Penalties and enforcement are covered on the hospital price transparency rule page, so we do not repeat them here.

Who owns CDM maintenance?

No federal rule names a department that must own the chargemaster, so the hospital assigns it. A common pattern is a small committee with one named owner who signs off on every change. Without a named owner, lines are added by whoever asks and removed by nobody.

Keep an effective date and a requester on every change. When an auditor or payer asks why a line changed, that record is the answer.

What is charge reconciliation?

Charge reconciliation compares the charges a department says it delivered with the charges that reached the claim. The term is common hospital usage, not a CMS term. The goal is to find revenue that was delivered but never billed, and charges that were billed twice.

How do we review the CDM for ER levels?

Review the ED visit lines to confirm the facility levels map to a documented, written leveling guideline. Under the Medicare Claims Processing Manual, chapter 4, section 160, hospitals bill a Type A emergency department with CPT emergency E/M codes and a Type B department with HCPCS G0380 to G0384 for levels 1 to 5, and hospitals use their own internal guidelines to level ED visits. The detail is on ED facility level coding.

• Confirm the ED type and that each level maps to the correct code family.
• Confirm each visit-level line uses revenue code 0450 or the family code your payers expect.
• Check that critical care, trauma activation and observation lines follow their own rules.
• Compare the distribution of levels with the written guideline and the documentation.

Documentation behind the levels is covered in the ED coding and documentation guide.

What tools help audit a CDM?

Most of the useful tools are free CMS files and your own claim data. You do not need a new system to find the first set of problems.

• The HCPCS quarterly files on the CMS website, to check every code on the CDM.
• The OPPS Addendum A and B snapshots, to see each code's status indicator and APC.
• Your claim scrubber edit report, to see which lines trigger edits most.
• Your remittance data, sorted by CARC and RARC, to find lines that cause denials.
• The posted machine-readable file, to compare the public view with the CDM.
• Sample claims, to trace a line from the CDM to the form locators.

How should a CFO prioritize CDM fixes?

Fix what costs money now before what looks untidy. The ranking below is our judgment and not a regulatory order. Move items up if your own denial or price file data points there.

How we handle chargemaster work

Our billing and coding audits review the codes, revenue codes and modifiers on your CDM lines against the current CMS files and against the claims and remits we see. Our hospital and facility billing team then tracks the denials those lines cause, so a fix is measured in fewer rejections and less rework. We validate revenue codes, bill type, patient status, condition and occurrence codes and payer-specific rules before claims leave.

We do not set your prices. Pricing policy, the posted file and the attestation stay with your hospital and your counsel. If you want us to look at how your CDM maps to claims, book a call.