Error code
L6 — Procedure already paid to another lab - fee adjusted to pay the difference
Paid the difference only
A related procedure was already paid to another laboratory, so your fee was reduced to pay only the difference.
What to do: Compare the amount paid with the listed fee; if the decision looks wrong, send a remittance advice inquiry within 7 months.
- Code
- L6
- Description
- Procedure already paid to another lab - fee adjusted to pay the difference
Explanation
Updated October 26, 2026
L6 means a related procedure was already paid to another lab, so this fee was reduced to pay only the difference.
What it means
L6 means a procedure was already paid to another laboratory and is not payable in addition to this one. Your fee was adjusted to pay the difference between the two.
How to fix it
- Compare the amount paid with the listed fee to confirm the difference was calculated correctly.
- If you believe the decision is wrong, send a Remittance Advice Inquiry (RAI) through eSubmit, or on form 0918-84, within 7 months of the RA date, with supporting details.
Don't resubmit if
- The line is already on your RA. Question it with an RAI, not a new claim.
How APEX handles it
APEX reads your error reports and remittance advice from MCEDT and lists claims rejected with this code in its Correction Centre for you to correct and resubmit. See how APEX works · Pricing