PR 66 denial code

Claim adjustment reason code 66. Often reported as PR 66.

Blood deductible applied

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 66 means

The payer did not pay for some units of blood because they fall under the patient's blood deductible.

Certain plans make the patient responsible for the first few units of whole blood or packed red cells in a benefit period, separate from the regular deductible. This code shows the amount the payer held back for those units.

It usually comes with group code PR. The patient can often meet the deductible by arranging replacement blood donations, depending on the plan, so the balance may change if donations are recorded.

Group codes seen with 66

On a remittance, 66 comes after a group code. These are the ones it is most often reported with:

• PR 66 (Patient Responsibility): The amount is assigned to the patient. Deductibles, coinsurance and copays are the everyday examples. Whether you can collect it still depends on your contract and the patient's plan.

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 patient received blood units early in the benefit period before the blood deductible was met.
• No replacement donation was recorded for the units furnished.
• The facility billed blood units with revenue and value codes that triggered the deductible.

What to do next

1. Confirm how many units the payer applied to the blood deductible and that the count matches the claim.
2. Check whether the patient or a donor replaced the blood, and send proof to the payer if the plan allows a credit.
3. Bill the remaining amount according to the group code and the patient's plan terms, after checking the remittance.
4. Make sure value codes for blood furnished and replaced were reported correctly on the institutional claim.

Related codes

• 1 (reason code) Amount applied to the deductible
• 2 (reason code) Patient's coinsurance share