Methodology
Where the data comes from, and where it runs out
This is a trust page, not a sales page. Our real coverage against the full CMS and X12 files, stated plainly, and how the confidence flag on every value actually works.
The datasets
Six sourced tables, curated subsets of much larger CMS and X12 files
NCCI procedure-to-procedure (PTP) edits
40,009 pairsColumn 1 / column 2 code pairs, the modifier indicator (0, 1 or 9), and the effective and deletion dates that decide which quarter each pair applies to. The full CMS PTP file runs to hundreds of thousands of rows across all provider types; we hold a curated subset.
Medically unlikely edits (MUE)
15,162 codesThe practitioner-services MUE value and adjudication indicator (MAI 1, 2 or 3) per code. CMS also publishes separate MUE tables for outpatient hospital and DME; we hold the practitioner table only.
X12 Claim Adjustment Reason Codes (CARC)
50 codesPlain-language meaning, why each code typically fires, ranked corrective actions, and an appeal-worthiness rating with the reasoning behind it. X12 maintains several hundred CARC values in active use; we hold the ones billers encounter most.
X12 Remittance Advice Remark Codes (RARC)
39 codesThe detail codes that usually accompany a CARC on a remittance, each with its own corrective actions. RARC values run into the thousands across X12's full list; we hold a curated subset paired with the CARCs above.
Modifiers
20 modifiersWhich modifiers CMS recognises as capable of bypassing a PTP edit, when each is genuinely appropriate, and when it is not. This list is what the scrubber checks a claim line against before reporting a PTP finding as bypassed rather than failed.
Timely filing and appeal windows
20 payersInitial claim filing limits and appeal windows by payer, where published. Many limits are contract-specific, so a payer with no entry here has no honest default: we say so rather than guess a number that could be wrong for your contract.
Every one of these numbers is read live from the shipped dataset when this page is built, so it cannot drift ahead of what the engine actually holds. If a data file has not finished loading for this deployment, the count above is honestly zero rather than a placeholder.
Confidence
What verified and unverified mean
What the confidence flag means
- Verified
- Read directly off the published CMS NCCI, MUE, or X12 page cited alongside it.
- Unverified
- Not confirmed on an official source. Shown for reference only, never presented as a checked fact.
A third case is not a confidence level at all: when we hold no edit for a code or pair, the finding status is not checked, never a pass. See methodology.
Quarterly edit versioning
CMS republishes NCCI PTP and MUE files every quarter. Each row carries an effective date and, where it applies, a deletion date. A claim is checked against the edit that was actually in force on its date of service, never against today's file. The resolved quarter (for example "2026 Q2") is part of every verdict and is what Pro's saved claim history records.
Coverage is a subset, and we say so
The full CMS NCCI PTP file spans every specialty and provider type; the full MUE tables cover practitioner, outpatient hospital and DME separately; X12's CARC and RARC lists run into the thousands combined. We publish a curated subset of each, and every scrub result states the exact pair and code counts it was checked against, so "not checked" is never silent.
Timely filing varies by contract
Where we hold a payer's published filing and appeal window, we cite it. Where a limit is set by an individual provider contract rather than a public policy, no honest default exists, and we show no value rather than a guess that could be wrong for your agreement.
CPT is AMA-copyrighted
CPT is a registered trademark of the American Medical Association. CPT code descriptors are copyrighted by the AMA and are not reproduced here. Procedure codes are referenced numerically, and all edit data comes from the publicly published CMS NCCI and MUE files.
FAQ
Coverage and confidence questions
What does "verified" mean on a value?
We read that exact value directly off the cited CMS or X12 page ourselves. It is not a guess, and it is not carried over from a secondary source we did not check.
What does "unverified" mean?
We could not confirm the value on an official source. It renders as Unverified rather than as a plain fact, and it should be treated as a starting point to check, not something to bill on. There is no third, in-between confidence tier: a value is either verified against the cited source, or it is not.
Why does a scrub result ever say not checked instead of pass?
Our PTP and MUE datasets are curated subsets of much larger CMS files. When we hold no row for a code or a pair, the honest answer is that we did not check it, not that it passed. Reporting a pass we did not earn would let a claim go out on a green light we never actually gave, so the finding status is "no data" and it is never rendered green.
How does quarterly versioning actually work?
CMS republishes the NCCI PTP and MUE files every quarter. Every PTP pair and MUE code carries an effective date and, where applicable, a deletion date. An edit applies to a claim only when the date of service falls on or after its effective date and strictly before its deletion date; if either date is missing or malformed, we do not apply the edit rather than assume it is live. The quarter used for a given verdict is derived from the date of service, not from today's date, and is recorded alongside every result.
Can I see procedure code descriptions?
CPT is a registered trademark of the American Medical Association. CPT code descriptors are copyrighted by the AMA and are not reproduced here. Procedure codes are referenced numerically, and all edit data comes from the publicly published CMS NCCI and MUE files.
DenialPath provides billing and administrative guidance based on published CMS and X12 sources. It is not medical advice, not a coverage determination, and not a guarantee of payment. NCCI and MUE edits are republished quarterly and payer policies vary by contract. Always confirm against the payer's own current policy before submitting or appealing.
See it applied to a real claim
The free scrubber shows the citation and edit quarter behind every verdict.