CO-197 means the payer denied your claim because the service needed authorization, precertification, or notification, and the payer has none on file. The “CO” puts the loss on your practice, not the patient. Find the cause before you act: a missing number on the claim is a corrected-claim fix, not an appeal.
Who this is for: you own, manage, or bill for a small California practice, and a remittance just came back with CO-197. This guide covers commercial plans and Medi-Cal managed care plans, with notes on Medi-Cal fee-for-service.
What does CO-197 mean?
Every denial on your remittance carries two parts. The remittance is the payment explanation the payer sends back, called an ERA (electronic remittance advice) or an 835 when it arrives electronically.
The first part is a two-letter group code. The second is a Claim Adjustment Reason Code (CARC), a national code maintained by X12, the standards body behind electronic claims. X12 defines CARC 197 as “Precertification/authorization/notification/pre-treatment absent.” In plain English: this service needed the payer’s approval or a heads-up first, and the payer has no record of one.
X12 lists four active group codes: CO (Contractual Obligation), OA (Other Adjustment), PI (Payer Initiated Reductions), and PR (Patient Responsibility). The group code tells you who carries the amount.
Can you bill the patient for CO-197?
No, not under a CO group code. CO means the payer considers the amount your responsibility under your contract. Noridian, a Medicare contractor, warns that billing a patient for charges not marked with the PR group code can lead to penalties. Check your payer contract before you send any statement.
If your remittance shows PR-197 instead, the payer has assigned that amount to the patient. Read the remark code before you bill anyone.
Read the remark code too
Most denials also carry a Remittance Advice Remark Code (RARC), which adds detail. Noridian’s guidance pairs CARC 197 with RARC N210, “Alert: You may appeal this decision.” Your payer’s remark code can be the fastest clue to which fix you need.
CO-197 vs the codes that look like it
Authorization problems arrive under at least eight different CARCs, and each points to a different fix. Payers don’t always pick the most precise one, so a CO-197 can hide an authorization that exists but doesn’t match the claim. Use this table to sort what you received.
| CARC | Official X12 description | What it usually points to | First move |
|---|---|---|---|
| 197 | Precertification/authorization/notification/pre-treatment absent. | No authorization on file for this service, or none linked to the claim | Search for an existing auth before anything else |
| 198 | Precertification/notification/authorization/pre-treatment exceeded. | You billed more units, visits, or days than approved | Compare billed units to approved units |
| 284 | Precertification/authorization/notification/pre-treatment number may be valid but does not apply to the billed services. | Auth covers a different CPT or HCPCS code | Ask the payer to update the auth, or correct the code |
| 296 | Precertification/authorization/notification/pre-treatment number may be valid but does not apply to the provider. | Auth issued to another NPI, location, or group | Ask the payer to move the auth to the rendering provider |
| 302 | Precertification/notification/authorization/pre-treatment time limit has expired. | Service fell outside the approved date range | Check the from-through dates on the auth |
| 210 | Payment adjusted because pre-certification/authorization not received in a timely fashion | Auth requested, but after the payer’s deadline | Appeal with proof of when you requested it |
| 39 | Services denied at the time authorization/pre-certification was requested. | Payer refused the auth before the visit | This is a medical-necessity fight, not a paperwork fix |
| 288 | Referral absent | HMO referral missing, a different requirement from authorization | Get the referral from the primary care provider |
One more trap: older billing guides still cite CARC 15 for a missing or invalid authorization number. X12 shows CARC 15 with a stop date of 05/01/2018. Codes 284 and 296, added in 2017 and 2018, now cover the mismatch cases.
Source: X12 Claim Adjustment Reason Codes, checked October 2026.
Which CO-197 do you have? Five causes and the fix for each
CO-197 has five root causes in practice, and only two of them call for a formal appeal. Work through them in this order. The first three are fixable without arguing with anyone.
1. The authorization exists, but it isn’t on the claim
This is the cheapest CO-197 to fix. On a paper CMS-1500 claim, the authorization number belongs in Item 23. On an electronic claim (an 837P), it goes in loop 2300, in a REF segment with the qualifier G1.
Fix: add the number and send a corrected claim under your payer’s corrected-claim rules. Don’t file an appeal for this. An appeal takes longer and asks a reviewer to judge something you can simply correct.
Medi-Cal fee-for-service note: a TAR (Treatment Authorization Request) is Medi-Cal’s authorization. DHCS requires the Pricing Indicator from the TAR’s Adjudication Response as the 11th digit of the TAR Control Number on the claim. DHCS states that claims without it will be denied. DHCS also requires TAR-authorized and non-TAR services on separate claims.
2. The authorization exists, but it doesn’t match
The auth was issued, but for a different provider, location, code, unit count, or date range. Payers are supposed to use CARC 284, 296, 198, or 302 here, but some return 197.
Fix: call the payer’s utilization management line and ask them to correct the authorization record first. Write down the date, the rep’s name, and the call reference number. Then send a corrected claim. If you rebill before the auth record changes, you’ll get the same denial back.
3. The authorization came from the wrong entity
This is the most California-specific cause. HMO and Medi-Cal managed care members can be assigned to a medical group or IPA (independent physician association) that handles authorizations for the plan. California’s utilization review timelines apply to health plans and their contracting IPAs and medical groups alike, which tells you how much of this work sits below the plan level.
If you got approval from the health plan but the member’s medical group handles authorizations, or the reverse, the claim can come back CO-197. The same thing happens when a patient’s plan changed between the authorization and the visit.
Medi-Cal adds one more version. DHCS states that fee-for-service TARs will be denied for members enrolled in a Medi-Cal managed care plan unless the plan has denied the service first. If the patient is in CalOptima, IEHP, L.A. Care, Health Net, Molina, or another managed care plan, the authorization runs through that plan.
Fix: pull the eligibility response for the date of service and find who held authorization responsibility that day. Request the authorization from that entity. Ask whether it can be issued retroactively, explained in cause 4.
4. Nobody requested an authorization
This is the hard one. You have three possible paths.
- Retro-authorization. Some plans accept a retroactive request within a set window. The window and the qualifying reasons vary by plan and by product line. Ask the payer directly and get the answer in writing.
- Emergency or urgent care. If the service was emergent, appeal with the clinical documentation that shows it.
- Coverage you couldn’t have known about. If the patient didn’t present this insurance at the visit, or their eligibility was added after the fact, appeal with the eligibility records and timeline. For Medi-Cal, California’s regulations allow retroactive authorization only in limited circumstances.
If none of these apply, the claim is likely a write-off. Under a CO group code, it isn’t the patient’s bill.
5. The service didn’t need authorization
A payer can misapply its own authorization list. If the CPT code, place of service, and plan type didn’t require authorization on the date of service, you have a strong appeal.
Fix: appeal with a copy of the payer’s authorization list as it stood on the date of service, plus any call reference where a rep confirmed no auth was needed. Save a dated PDF of the payer’s list whenever you check it. Lists change, and you’ll need the old version.
How to appeal a CO-197 denial in California
For plans licensed by California’s Department of Managed Health Care (DMHC), the formal appeal is called a provider dispute. It runs under Title 28, California Code of Regulations, section 1300.71.38, and the same rules reach the medical groups and IPAs those plans pay to handle claims.
The California deadlines
| Step | Deadline | Who it binds |
|---|---|---|
| You file the dispute | Within 365 days of the plan’s action | You |
| Plan acknowledges an electronic dispute | 2 working days | The plan |
| Plan acknowledges a paper dispute | 15 working days | The plan |
| You resubmit a dispute the plan returned as incomplete | 30 working days from receipt of the returned dispute | You |
| Plan issues a written decision | 45 working days | The plan |
DHCS confirmed the 365-day filing window and these processing timelines for Medi-Cal managed care plans in All Plan Letter 26-017. Track the plan’s side of the clock too. In February 2026, DMHC fined Health Net $450,000 after finding it repeatedly missed the 15-working-day acknowledgment and 45-working-day resolution deadlines.
These rules don’t cover every payer. Self-funded employer plans, Medicare Advantage plans, and insurance policies regulated by the California Department of Insurance may follow different appeal processes. The appeal instructions on the denial or in the payer’s provider manual name the process that applies.
What goes in a CO-197 appeal packet
A CO-197 appeal wins or loses on documents, not arguments. Send everything the reviewer needs to reverse the denial without calling you.
- The payer’s dispute form, if it has one. Molina, for example, requires its own Provider Dispute Resolution Request Form.
- A copy of the claim as submitted.
- The remittance page showing CO-197 and any remark code.
- The authorization approval, showing the number, code, units, date range, and provider.
- The eligibility response for the date of service, showing the plan and any medical group or IPA.
- Your call log: dates, rep names, and call reference numbers.
- The payer’s authorization list as of the date of service, if you’re arguing no auth was required.
- Clinical documentation, only if you’re arguing the service was emergent or urgent.
- A one-page letter that names the cause and the action you want.
Send the packet only through the payer’s secure portal or its listed dispute address. Never email patient records.
A letter structure that works
Keep it to one page. The reviewer should know what you want in the first two sentences.
Re: Provider dispute, Claim # [CLAIM NUMBER], Date of service [DATE]
Denial: CO-197 (Precertification/authorization/notification/pre-treatment absent)
We request reprocessing and payment of this claim. Authorization
[AUTH NUMBER] was approved on [DATE] for [CPT CODE], [UNITS] units,
[DATE RANGE], for [RENDERING PROVIDER, NPI]. The service on the claim
falls within that approval. A copy of the approval is enclosed.
Enclosed: claim copy, remittance, authorization approval,
eligibility response, call log with reference numbers.
[NAME, TITLE, PRACTICE, PHONE]Swap the middle paragraph for the cause you identified: the payer’s own authorization list, the emergency documentation, or the eligibility timeline.
How fast payers must answer an authorization request in 2026
Payers now have short, fixed clocks for authorization decisions, which removes “there wasn’t time” as a reason to skip one. Two sets of rules apply in California.
| Rule | Applies to | Standard request | Urgent request |
|---|---|---|---|
| CMS-0057-F, effective January 1, 2026 | Medicare Advantage, Medi-Cal fee-for-service and managed care, CHIP | 7 calendar days | 72 hours |
| CA Health & Safety Code 1367.01 and Insurance Code 10123.135 | California health plans, insurers, and their contracting IPAs and medical groups | 5 business days after the payer has the information it needs | 72 hours |
The federal rule also requires these payers to give a specific reason when they deny an authorization request, starting in 2026. Prescription drugs are excluded. Under California law, the payer must tell you the decision within 24 hours of making it.
What this means for CO-197: a request sent when you book the visit should come back before the visit, if the payer meets its deadline. Build the request into scheduling, and keep a copy of the decision and its reason in the patient’s billing record.
For which therapy services need authorization from each California payer, see our therapy prior authorization guide.
How to stop CO-197 denials before they happen
CO-197 is a front-desk problem that shows up in billing. Fix the intake process and the denials stop arriving. These seven controls cover every cause above.
- Keep a payer-by-code authorization grid. One row per payer, plan type, and CPT or HCPCS code, with a yes or no for authorization. Save a dated PDF of each payer’s list whenever you update the grid.
- Check eligibility at scheduling and again before the visit. Note who handles authorization: the plan, a medical group, or an IPA. A patient’s plan can change mid-treatment.
- Record the full authorization, not just the number. Code, units, date range, rendering provider NPI, and location. Cause 2 comes from skipping this step.
- Track units used against units approved. Request an extension before the last approved visit, not after it.
- Add a claim scrubber rule. Block any claim for an authorization-required code when Item 23 (or loop 2300 REF G1) is empty.
- Split Medi-Cal fee-for-service claims. Bill TAR-authorized and non-TAR services on separate claims, with the Pricing Indicator as the 11th digit of the TAR Control Number.
- Review authorization denials weekly by root cause. Group CARCs 197, 198, 284, 296, and 302 together. The pattern tells you which step in your front desk is breaking.
For the wider picture of why claims bounce, see why claims get denied. If you’re a doula billing Medi-Cal, our Medi-Cal doula denial guide covers the denials specific to that benefit. If you’d rather hand the whole authorization workflow to someone else, that’s what our prior authorization service does.
CO-197 questions practice owners ask
Is CO-197 the same as PR-197?
The reason is the same: no authorization on file. The group code differs. CO-197 puts the amount on your practice under your contract. PR-197 assigns it to the patient.
How long do I have to appeal CO-197 in California?
For DMHC-licensed health plans and Medi-Cal managed care plans, you have 365 days from the plan’s action to file a provider dispute. Other payers set their own windows, so check the denial notice.
What’s the difference between CO-197 and CO-198?
CO-197 means no authorization was found. CO-198 means an authorization exists, but you billed beyond what it approved, such as extra visits or units.
Can I get an authorization after the visit?
Sometimes. Retroactive authorization depends on the payer, the plan type, and the reason you didn’t get one in advance. Ask the payer and get the answer in writing before you rely on it.
Get help with CO-197 denials
Claim N Billing is a family-owned billing company in Irvine. We started by fixing the billing for our own non-emergency medical transportation company, then took that work to other small California practices. CNB holds a 98% clean claim rate, and we work authorization denials across Medi-Cal managed care and commercial plans.
If CO-197 keeps showing up on your remittances, our denial management and appeals team can find the root cause and work the backlog. Start with a free billing audit, book a call, or phone us at 949-969-4397.
This article describes billing requirements in general terms. It isn’t legal or compliance advice. Confirm requirements with your payer or your compliance counsel.