Quick Explanation
Denial code CO-135 indicates that the payer is unable to process an interim bill submitted for a portion of an ongoing patient stay or treatment course. This typically occurs when payer policies require a single consolidated final claim upon discharge, or when interim claims are submitted out of chronological sequence.
Common Causes for CO-135
Denials with code CO-135 typically happen for the following specific reasons:
- Submitting interim Type of Bill (TOB) codes (such as 112 or 113) to a commercial payer whose policy does not contractually allow or support interim billing.
- Submitting interim claims out of chronological sequence, which causes the payer's system to reject the claim due to a missing prior billing period.
- Failing to submit a final discharge claim (TOB 114 or 111) when required by the payer to trigger the processing and reconciliation of previously submitted interim claims.
- Submitting an interim bill for an inpatient or skilled nursing facility stay that does not meet the minimum length of stay or monetary threshold required by the payer's guidelines.
How to Prevent CO-135 Denials
To avoid receiving this denial in the future, implement these specific checks:
- Verify each payer's specific billing guidelines and contract terms regarding interim billing and Type of Bill (TOB) requirements during the pre-authorization or admission phase.
- Implement an automated billing queue or tracking system to ensure all interim bills (TOBs ending in 2, 3, or 4) are submitted in strict chronological sequence.
- Convert billing to a single, comprehensive discharge claim (e.g., TOB 111) upon patient discharge if the commercial plan does not support interim payments.
- Regularly audit active long-term cases to ensure the length of stay and clinical documentation meet the Medicare or commercial threshold required to qualify for interim billing.
Appeal Letter Template for CO-135
If you believe this claim was denied incorrectly, you can use the following template to submit an appeal.
[Your Practice Header]
[Date]
[Payer Name]
[Appeals Department Address]
RE: Appeal for Claim [Claim Number]
Patient: [Patient Name]
ID: [Patient ID]
Date of Service: [Date]
Denial Code: CO-135 - Interim bills cannot be processed
Dear Appeals Department,
I am writing to appeal the denial of the above-referenced claim, which was denied with code CO-135: "Interim bills cannot be processed".
This appeal is submitted to request reconsideration for the denied interim claim under Type of Bill (TOB) [Insert TOB, e.g., 112/113]. In accordance with the CMS Medicare Claims Processing Manual Chapter 1, Section 50, and standard institutional billing guidelines, interim progress bills are fully permitted for prolonged inpatient and skilled nursing stays to avoid administrative and financial hardship. The patient's continuous stay from [Insert Start Date] to [Insert End Date] meets all clinical and administrative criteria for interim billing, and all preceding claims in this sequence have been submitted chronologically. We request that this interim claim be processed and paid in accordance with industry-standard sequential billing guidelines.
Attached please find:
1. A copy of the original claim.
2. The relevant medical records supporting the service.
3. [Any other supporting documents].
We respectfully request that you reprocess this claim for payment.
Sincerely,
[Your Name]
[Title]
[Practice Name]
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