CO 240 denial code

Claim adjustment reason code 240. Often reported as CO 240.

Diagnosis conflicts with birth weight

Unofficial reference. This is our own plain-English explanation, not the official code text. Payer rules differ. Verify with the payer and the official X12 code list. AlphaPrefix is not affiliated with X12, CMS or any payer. Data last updated Nov 11, 2026.

What 240 means

A diagnosis code on the claim does not make sense for the birth weight reported for the newborn.

This edit checks newborn claims. Some diagnosis codes describe specific birth weight ranges, and the payer found that the code and the reported weight disagree.

A policy reference may be on the remittance. The fix is usually a coding or data entry correction.

Group codes seen with 240

On a remittance, 240 comes after a group code. These are the ones it is most often reported with:

• CO 240 (Contractual Obligation): The provider's side of the ledger. The reduction comes from the payer contract or a rule the provider has to follow, and the patient normally cannot be billed for it.

The payer chooses the group code for each adjustment, so the same reason code can appear with another group code on your remittance. Read the two together. More about group codes.

Common causes

• A low birth weight diagnosis was coded for a newborn whose reported weight was normal.
• The birth weight value was entered in the wrong units or with a typo.
• A diagnosis for a different weight range was picked by mistake.

What to do next

1. Check the birth weight in the record against the weight on the claim.
2. Pick the diagnosis code that matches the documented weight range.
3. Send a corrected claim with the matching weight and diagnosis.

Related codes

• 16 (reason code) Missing information or billing error
• 9 (reason code) Diagnosis does not fit the patient's age