CO 153 denial code

Claim adjustment reason code 153. Often reported as CO 153.

Records do not support dosage

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 153 means

The payer decided the documentation does not justify the dose of the drug or product that was billed.

The payer is questioning how much of a drug or product was given, not whether it was covered. It may pay for a lower dose or deny the line.

Check that the billed units match the dose in the record after converting to the billing unit for the code. Conversion errors are a frequent cause.

Group codes seen with 153

On a remittance, 153 comes after a group code. These are the ones it is most often reported with:

• CO 153 (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

• The billed units did not match the dose documented in the record.
• The dose given was above the payer's accepted dosing guidelines without a stated reason.
• The drug's billing unit was converted incorrectly when calculating units.

What to do next

1. Compare the dose in the administration record with the units billed.
2. Recalculate units using the billing unit for the drug code.
3. Appeal with the order and clinical reasons if a higher dose was medically needed.

Related codes

• 154 (reason code) Records do not support day's supply
• 188 (reason code) Not used per FDA recommendations