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CO-B15: the add-on administration code has no qualifying primary code on the claim

CO-B15 · drug and administration lines · fix · appeal

CO-B15 says the service requires a qualifying service that the payer has not received or covered. On administration lines it means an add-on code — each additional hour, sequential infusion, additional push — was billed without a payable initial code on the same claim and date. Add-ons cannot stand alone.

Reviewed Sep 20, 2026 · maintained by Erin Rose · general reference, not legal advice

What the remit says

CO-B15 — “This service/procedure requires that a qualifying service/procedure be received and covered. The qualifying other service/procedure has not been received/adjudicated.”

Verbatim, X12 code lists 11/1/2025.

Why it lands on drug claims

96366 (additional hour), 96367 (sequential new drug), 96368 (concurrent), 96375 (additional push), 96415 and 96417 (chemo additional hour and sequential) are CPT add-on codes: each is defined as reportable only with a specified primary. If the initial code is not on the claim, is on a separate claim for the same date, or was itself denied (CO-97, CO-151), the add-on has nothing to attach to and returns CO-B15.

The two common shapes: (1) the initial code was denied for another reason and the add-on fell with it — fix the initial denial and the add-on pays on the same corrected claim; (2) the encounter was split across two claims, say the drug and its infusion on one and the hydration hour on another. Add-ons and their primary must travel together.

One shape that is not a B15 problem: 96361 hydration add-on with no 96360. CPT and NCCI direct that hydration before or after another initial service is reported as 96361 against that initial code, so a claim with 96365 and 96361 is correct. If it returns B15, the payer's edit is wrong and that is an appeal with the CPT guideline attached.

The fix

What to attach

Corrected claim or appeal?

Corrected claim: put the add-on and its initial code on one claim for one date and resubmit. The exception is 96361 denied beside a non-hydration initial code — that is a payer edit error and an appeal with the CPT hydration guideline attached.

Medicare windows (redetermination 120 days, reconsideration 180 days, ALJ 60 days) and the commercial path are on the denials hub, cited to 42 CFR Part 405 Subpart I; the edits are CMS's NCCI tables.

Frequently asked

The 96365 paid on a claim last week and the 96366 is on this one. Why B15?
Because the qualifying service has to be on the claim the payer is adjudicating. Add-ons are not matched across claims. Void this claim and resubmit the 96366 on a corrected version of the one that carried 96365.
Can 96367 be billed without 96365 if the primary service was 96413?
Yes. 96367 attaches to any initial infusion or injection code — 96413 qualifies. A B15 on that combination is a payer edit error; appeal with the CPT add-on parent list for 96367.
Does CO-B15 mean the add-on is not covered?
No, it means it is unattached. Coverage is not in question; once the primary is present and paid, the add-on adjudicates on its own merits (units, MUE, medical necessity).

Related references

96365 and 96366Initial hour and each additional hour96367 and 96368Sequential and concurrent infusionsCPT administration codesThe full initial/add-on hierarchyAll drug-claim denialsThe ten denials that land on infusion and injection claims

Add-ons attached to their primary, automatically

Claim Check builds the encounter as one claim — initial code first, add-ons under it by the hierarchy — so 96366 and 96367 never travel without the line they depend on.

Open Claim Check

Sources & how this is maintained

Computed on this page
Nothing — this denial has no table fact; the code text is verbatim X12. Edits vintage Q3 2026.
Authored
The two claim shapes that produce B15, and the 96361 case that looks like one but is not.
Corrections
Send one with the remit line.