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N378 Remark Code: Prescription Quantity Missing/Invalid

N378 means the quantity prescribed for a drug or supply was missing, incomplete, or invalid on the claim, so the payer could not confirm that the amount dispensed or billed matches the prescription.

Quick facts

Code
N378 (RARC N378)
Status
Active In use since December 1, 2006.
Code set
Remittance Advice Remark Codes (RARC)
Group codes
  • CO (Contractual Obligation): The claim was denied for a correctable problem with the prescription quantity. The provider or supplier fixes it; the patient is not billed.
Official description
Missing/incomplete/invalid prescription quantity.
X12 Remittance Advice Remark Codes, retrieved September 25, 2026
Last verified
against the official X12 list.

What N378 means

For items dispensed from a prescription, payers compare what was ordered with what was supplied and billed. The prescription quantity is the anchor for that comparison. N378 says it was absent, only partly reported, or didn’t make sense (such as zero, a negative number, or an amount inconsistent with the days’ supply).

It usually explains CARC 16. When the quantity leads the payer to question the days’ supply or dosage, CARC 154 or 153 may appear.

Common causes

  • The quantity field was left blank because the billing system didn’t map it from the dispensing record.
  • The quantity was reported in the wrong unit of measure (for example, boxes instead of individual items).
  • The total for all refills was reported instead of the amount for this fill.
  • The quantity didn’t agree with the days’ supply and dosing directions.
  • Prescription changes weren’t reflected in the billing record.

How to fix it

  1. Review the prescription or order and the dispensing record for this fill.
  2. Confirm the unit of measure the payer expects, and convert if needed.
  3. Make sure quantity, days’ supply, and billed units all agree with each other and with the directions.
  4. Correct the claim and resubmit with frequency code 7 and the original claim number, or follow the pharmacy reversal-and-rebill process for pharmacy claims.
  5. If the quantity exceeds the payer’s limits, obtain any required authorization before refilling.

How to prevent it

Pull quantity directly from the dispensing system into the claim rather than retyping it. Set unit-of-measure conversions per payer, and flag claims where quantity divided by daily dose doesn’t match the days’ supply.

Codes that may appear with N378

  • CO-16 (Claim/service lacks information or has submission/billing error(s).): Claim information is missing or invalid; N378 identifies the prescription quantity.
  • CO-154 (Payer deems the information submitted does not support this day's supply.): The payer deems the information doesn't support this day's supply.
  • CO-153 (Payer deems the information submitted does not support this dosage.): The payer deems the information doesn't support this dosage.
  • N388 (Missing/incomplete/invalid prescription number.): Used when the prescription number is missing or invalid.
  • M123 (Missing/incomplete/invalid name, strength, or dosage of the drug furnished.): Covers a missing or invalid drug name, strength, or dosage.
  • N57 (Missing/incomplete/invalid prescribing date.): Addresses a missing or invalid prescribing date.

N378 FAQ

Is prescription quantity the same as billed units?

Not necessarily. The prescription quantity is what the prescriber ordered, while billed units depend on the code's unit definition. Both need to be consistent with each other.

Which claims report a prescription quantity?

Pharmacy claims, and some medical claims for drugs, DME supplies, and other items dispensed under a prescription. Payer requirements vary.

What if the prescription allowed refills?

Report the quantity dispensed for this fill as the payer instructs, not the total across all refills.