Claims · Updated 2026-09-08 · 5 min read

What is the difference between CO-97, CO-96 and PR-96?

97 means bundled into another service. 96 means non-covered and names no rule at all. CO and PR decide who pays. How to tell the three apart on a dental EOB.

97 and 96 are different events and the group letters in front of them are a third thing again. 97 means the benefit for this service is included in the payment for another service already adjudicated — bundling, and the office's question is whether the two codes really were one service. 96 means non-covered charge, and it is a money bucket rather than a reason: the X12 standard requires at least one remark code beside it because the code itself carries no cause. CO or PI in front means the dentist writes it off; PR means the patient owes it. As of September 2026, across 37 dental practices, procedures denied as bundled into another were 3,306 lines, 5.0% of all denied lines, while procedures denied as not covered by the plan were 14,609 lines and 22.3% — the single largest denial class in what we measured across 37 practices.

What we measured

Every adjudicated line for that code at that carrier, paid and denied, all dates: what we saw across 37 dental practices, measured September 2026. A carrier's rate reflects how its practices bill as much as the carrier's own rules — a practice that checks bundling before submitting produces fewer of these — so read these as our measurement, not as the carrier's policy.

The bottom row is the one to act on. A code bundled on 100% of its lines at a carrier is not a denial to appeal; it is a code that carrier never pays separately. The top row is the opposite: Cigna bundled 260 of 563 core-buildup lines; the other 303 were adjudicated some other way. A code that goes both ways at one carrier is one where what is on the claim can change the outcome.

What the carriers' own documents say

Delta Dental maps 42 of its 938 internal policy codes to CARC 97 and states the mechanism in its own words. The general bundling rule, policy code 718, printed as PR to a non-participating dentist and PI to a participating one:

"According to our guidelines, the fee for this procedure is considered to be part of, and included in the fee for a completed service. Please refer to Section 4 of the Dentist Handbook for information regarding dental policy and clinical guidelines for this service."

And the x-ray rule that produces most of the radiograph rows above, policy code 1V1, written off both ways:

"The combined fees for radiographic images are equal to or more than the fee for a complete radiographic image series. Therefore, according to our guidelines, the radiographic images are considered to be equivalent to a complete series."

Both from Delta Dental — Policy ID Mapping for CARC/RARC Health Care Policy Codes, pinned at Delta Dental of California network scope. The same table is the best available evidence for what 96 does not tell you: 433 of Delta's 938 policy codes — 46% — all arrive on the remittance as 96. A waiting period, a missing tooth limitation, a bleaching restriction and a denture relining limit are one code by the time they reach the office.

Why it depends on the contract

The number says what happened; the group letters say whose money it is, and the same number goes both ways. Delta prints two codes under CARC 204 with opposite groups, and it does the same across the 97 family: bundling code 718 is PR for a non-participating dentist and PI for a participating one, while 1V1 is PI for both. A contracted dentist writing off a 97 and a non-contracted dentist billing it are both reading their own contract correctly.

That is also why "can I bill this?" cannot be answered from a 96. Delta files waiting periods, missing tooth limitations and frequency caps under it as PR, and files bundling rules under it as PI. The code is identical and the answer is not.

What to do

• On a 97, check whether a genuinely separate service was performed. If it was, appeal with the narrative and the images. If the two codes describe one procedure, write it off.
• Learn which codes your top carriers never pay separately, and stop billing them as separate lines. A code bundled on every line is a fee schedule fact, not a claims problem.
• On a 96, ignore the number and read the remark code and the sentence. That is where the actual rule is, and 96 with nothing beside it is a denial with no stated cause.
• Check the group letters before quoting anything to the patient. PI and CO are write-offs; PR is billable at the contracted allowance for an in-network dentist.
• For radiographs, price the combination before submitting. Where separate films add up to the full-mouth series fee, carriers re-price them as the series.
• Record the bundling pairs you confirm — buildup into crown, periapical into series, pulp cap into restoration — in the plan record, so the estimate reflects them before the patient is quoted.

Numbers last refreshed September 2026.

All articles · Kaylie