5.4 Billing and Claims Processing

The Two Core Claim Forms

Which form a provider uses depends on whether the biller is an institution (hospital, facility) or a professional (physician, individual provider):

The electronic equivalents are HIPAA-mandated ASC X12 837 transactions: 837I for institutional and 837P for professional claims. A frequent RHIT distractor swaps these — facility = UB-04/837I, professional = CMS-1500/837P.

Revenue Codes, the Chargemaster, and Code Sets

On the UB-04, every charge line carries a revenue code — a 4-digit code identifying the department or cost center that produced the service (e.g., 0450 emergency room, 0250 pharmacy). The revenue code answers where/what type; the CPT/HCPCS code answers exactly which procedure. Many payers require the revenue code and the CPT/HCPCS to be consistent.

The chargemaster (CDM) is the engine behind facility billing: it links each billable item to its description, revenue code, CPT/HCPCS, and price. Errors in the CDM propagate to every claim, so it must be maintained and audited continuously.

Code sets at a glance

• ICD-10-CM — diagnoses (all settings)
• ICD-10-PCS — inpatient procedures
• CPT — physician/outpatient procedures (HCPCS Level I)
• HCPCS Level II — supplies, drugs, services not in CPT
• Modifiers — two-character add-ons that refine a CPT/HCPCS code (e.g., laterality, distinct service)

Edits and Adjudication

Before submission, a claim scrubber runs claim edits to catch errors. Two federal edit systems are heavily tested:

• NCCI Procedure-to-Procedure (PTP) edits prevent unbundling — billing separately for services that should be reported together. In an edit pair, the Column 1 code pays and the Column 2 code is denied unless a clinically appropriate modifier is allowed. The modifier indicator controls this: 1 = an appropriate modifier (such as modifier 59, distinct procedural service) may bypass the edit; 0 = no modifier is permitted.
• Medically Unlikely Edits (MUEs) cap the maximum units of service for a single CPT/HCPCS code for one patient on one day, blocking improbable quantities.

After the payer adjudicates, the provider receives a remittance advice (RA) (electronic 835) showing payments, contractual adjustments, and denial/remark codes; the patient receives an explanation of benefits (EOB) — not a bill — summarizing what was billed, allowed, paid, and owed.

Trap: The EOB is informational and goes to the patient; the RA (835) goes to the provider and drives payment posting. Confusing the two is a common exam error.

The Claim Lifecycle, Step by Step

A claim moves through a predictable path, and HIM touches the front of it:

1. Coding and abstracting — the encounter is coded (ICD-10-CM/PCS, CPT/HCPCS) and key data abstracted.
2. Charge reconciliation — captured charges are matched against the chargemaster.
3. Claim generation — the billing system builds the UB-04/837I or CMS-1500/837P.
4. Scrubbing — internal and federal edits run; failed claims are corrected before they ever reach the payer.
5. Clearinghouse — a clearinghouse validates format, translates if needed, and routes the claim to the correct payer.
6. Adjudication — the payer applies coverage, benefits, and its own edits, then pays, reduces, or denies.
7. Posting and reconciliation — the 835 remittance is posted; underpayments and denials are flagged for follow-up.

The Role of the Clearinghouse

A clearinghouse is an intermediary that accepts claims from many providers, checks them against format and basic eligibility rules, and forwards them to the appropriate payers (and returns the 835 and rejection reports). Catching a formatting error at the clearinghouse — before adjudication — is far cheaper than working a denial after the fact, which is why clearinghouse rejection reports are a daily HIM/billing workflow.

Timely Filing, ABNs, and the UHDDS Link

Timely-filing limits require a claim to reach the payer within a set window (Medicare is generally one calendar year from the date of service; commercial payers vary, often 90–180 days). Miss the window and the claim is denied with no appeal on the merits — a fully preventable, and unrecoverable, loss. A coding backlog that pushes accounts past timely filing is therefore a direct revenue leak.

An Advance Beneficiary Notice of Noncoverage (ABN) is given to a Medicare patient before a service Medicare is likely to deny, so the patient can choose to accept financial responsibility. Without a valid ABN, the provider — not the patient — eats the cost of a non-covered service.

Data quality starts with UHDDS

The Uniform Hospital Discharge Data Set (UHDDS) defines core inpatient data elements — including the principal diagnosis definition that drives MS-DRG assignment — so claims are comparable across hospitals. Clean, standardized data at the point of coding is what makes accurate billing and downstream analytics possible. Garbage in at coding becomes denials and bad statistics out.

The principal diagnosis under UHDDS is defined as the condition established after study to be chiefly responsible for the admission — not simply the most severe condition or the admitting diagnosis. Choosing the wrong principal diagnosis can land the case in the wrong MS-DRG entirely, which is both a payment error and a compliance exposure. RHIT items frequently test this exact definition against tempting distractors such as "the most resource-intensive condition."