RemitBench/Denial codes/CO-146

CO-146 denial code

Code 146 is a calendar problem. The diagnosis code you used was not in force on the date you provided the care, usually because the code set changed and something in your system did not.

The code list's own wording: Diagnosis was invalid for the date(s) of service reported.

What it means: Diagnosis codes are added and retired on a schedule. The one on your claim was not active on the date of service, so the payer could not use it whatever it means clinically.
Who owes the money: Nobody yet Nothing was decided about coverage. Do not bill the patient for a code set problem.
Is appealing worth it: No. Correct the code for that date and resend.

This code has a season. Diagnosis code sets change on a fixed annual schedule, and this denial spikes immediately afterwards. If you are seeing several at once, the cause is almost certainly a stale list of favourites in your software rather than anything about the individual claims.

Why the payer sent it

The code was retired before the date of service.
The code was created after the date of service, which happens on late filed claims.
A favourites or quick pick list in your software still holds the retired code.
The date of service on the claim is wrong, so a valid code looks invalid.
A code was replaced by a more specific set and the general one no longer exists.

Remark codes you will see with it

Remark code	What it adds
M76	Missing, incomplete or invalid diagnosis.
MA130	Unprocessable claim, no appeal rights. Resubmit.

Remark code

What it adds

M76

Missing, incomplete or invalid diagnosis.

MA130

Unprocessable claim, no appeal rights. Resubmit.

Read the letters in front of the 146

CO-146: Contractual obligation. Correct it rather than absorbing it.
PI-146: Payer initiated. Not the patient's money.

What to do next

Check the date of service before the code

A wrong date makes a valid code invalid. It is the cheaper of the two things to check.
Find the code that was valid on that date

Not the code that is valid today. Late filed claims need the code set as it stood on the date of service, which catches people out.
Clean the favourites list

The step that stops the recurrence. If a retired code is stored as a quick pick, every user in the practice will keep choosing it.

Codes that get mixed up with 146

Code	How it differs from 146
181	The procedure code was invalid on that date. The same problem, other field. See CO-181.
182	The modifier was invalid on that date. See CO-182.
11	The diagnosis does not support the procedure. Valid code, wrong pairing. See CO-11.
167	The diagnosis is not covered. Valid code, excluded condition. See CO-167.

Codes 146, 181 and 182 are the same denial applied to three different fields. All three are calendar problems and all three are corrected claims.

Code 146 in dental

Only relevant when you bill medical, because ordinary dental claims carry no diagnosis. For practices that cross code, this is a January and October problem depending on the code set, and it is worth diarising a check of the stored codes at those points.

Questions people ask about CO-146

Why did a diagnosis we always use suddenly become invalid?

Because diagnosis code sets are updated on a fixed annual schedule and codes get retired or replaced. If your software holds a favourites list, it will keep offering the retired code long after the payer stopped accepting it, which is why these denials arrive in clusters rather than one at a time.

Related codes

Back to all denial codes

RemitBench reads dental EOB PDFs and turns them into posting-ready lines, in your browser, with no upload. It does not read medical remittances today.

Open the app

Opens your mail app with the message written. Nothing is sent from this page.