Claim adjustment reason code
Denial code PR-66 meaning
CARC 66, usually seen as PR-66: The patient owes the blood deductible for units of blood.
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- Reason code
- CARC 66
- Short name
- Blood deductible
- Plain meaning
- The patient owes the blood deductible for units of blood.
- Group codes
- PR-66: Patient responsibility. The patient, or a secondary payer, may owe the amount.
Plain-English summary written by Rivvi. X12 owns the CARC list and its exact wording, which is not reproduced here. Read it on the X12 CARC list (list dated November 1, 2025, checked October 23, 2026). This page does not decide how a claim is paid.
Common causes
- Under Medicare, the patient pays for the first 3 units of blood in a year unless they are replaced.
What to check before resubmitting
- Check whether the blood was replaced.
- Bill the patient or secondary payer.
Related reason codes
Related pages
Questions
What does denial code PR-66 mean?
The patient owes the blood deductible for units of blood. This is Rivvi's plain-English summary of CARC 66. X12's exact wording is on x12.org.
How do I fix PR-66?
Check whether the blood was replaced. Bill the patient or secondary payer.
Can I bill the patient for PR-66?
When it comes with group code PR, the patient or a secondary payer may owe the amount. When it comes with CO, the provider writes it off.
Which group codes come with CARC 66?
Most often PR (patient responsibility). The group code, not the reason code, says who owes the amount.
What is the difference between a CARC and a RARC?
A claim adjustment reason code (CARC) says why a claim line was paid differently than billed. A remittance advice remark code (RARC) adds detail, such as which field is missing.