RemitBench/Denial codes/CO-6

CO-6 denial code

Code 6 compares the procedure against the patient's age and finds them inconsistent. Very often the procedure is right and the date of birth is wrong.

The code list's own wording: The procedure/revenue code is inconsistent with the patient's age.

What it means: The payer has an age rule for that procedure and the age it holds for the patient falls outside it. Either the procedure is genuinely age restricted, or the age the payer holds is wrong.
Who owes the money: Nobody yet Nothing was adjudicated on the merits. Do not bill the patient while the claim is still unusable.
Is appealing worth it: Not usually. If the age is wrong, correct the claim. If the age is right and the rule is real, this is closer to a benefit limit and the remark will normally say so.

Check the date of birth first, every time. A transposed birth year is the single most common cause of a 6, and it takes ten seconds to check against the chart. Working the procedure code first wastes the afternoon on a claim whose only problem is a typo.

Why the payer sent it

The date of birth on the claim is wrong.
The payer holds a different date of birth from the one you have, which is an eligibility record problem.
The procedure genuinely has an age limit under the plan.
A paediatric code was billed for an adult, or the other way round.
The service is covered at that age but only with documentation, which usually arrives with remark N129.

Remark codes you will see with it

Remark code	What it adds
N129	Not eligible due to the patient's age. Confirms this is a benefit rule rather than a typo.
N130	Read the plan document for the age limits. Its own page.
MA130	The claim is unprocessable, so no appeal rights attach. Resubmit rather than appeal.

Remark code

What it adds

N129

Not eligible due to the patient's age. Confirms this is a benefit rule rather than a typo.

N130

Read the plan document for the age limits. Its own page.

MA130

The claim is unprocessable, so no appeal rights attach. Resubmit rather than appeal.

Read the letters in front of the 6

CO-6: Contractual obligation. Normal, and it should never stay a write-off if the cause is a typo.
PI-6: Payer initiated. Not the patient's money.
PR-6: Patient responsibility. Seen where the age limit is a real benefit rule rather than a data error.

What to do next

Compare the date of birth on the claim against the chart

Ten seconds, and it resolves a large share of these.
If it is wrong: corrected claim, and fix it in the patient record so it does not recur.
Ask the payer what date of birth they hold

Yours can be right and theirs wrong. That is an eligibility record correction, which the patient usually has to start with their employer or the plan.
Check whether the code has an age band

Some procedures are defined for a specific age range. If you billed the adult version for a child, the fix is the right code rather than an argument.
If the age rule is real, find the covered alternative

Plans that restrict a procedure by age usually cover something else for that age. Knowing what turns a denial into a treatment plan.

Codes that get mixed up with 6

Code	How it differs from 6
7	The procedure is inconsistent with the patient's gender. The same shape, a different field.
9	The diagnosis is inconsistent with the patient's age. Diagnosis rather than procedure.
140	The patient identification number and name do not match. Another identity mismatch. See CO-140.
16	The general claim error code. See CO-16.

Code 6 in dental

Dentistry has more age rules than most specialties, and they are real benefit rules rather than coding errors: fluoride to a certain age, sealants on children, space maintainers, preventive frequency for under a certain age. So a dental 6 is worth reading carefully instead of assuming a typo.

The common dental age rules

Fluoride treatment covered only up to a stated age.
Sealants covered only for children, and often only on specific teeth.
Space maintainers covered only while primary teeth are present.
Some plans covering an extra cleaning a year for children only.

Tell the family the age, not the denial

An age rule has a date attached to it, and the date is usually a birthday that has just passed. Families accept that far more easily than a denial, and it also tells them what to expect for a younger sibling.

Questions people ask about CO-6

Why did a routine procedure get denied for the patient's age?

Usually because the date of birth on the claim is wrong, which is the first thing to check. If the birth date is right, the plan probably has a genuine age rule for that procedure, and a remark such as N129 will normally confirm it.

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.