Error code
L3 — Not allowed in addition to other laboratory procedure(s)
Lab procedures can't be combined
This lab procedure can't be paid on top of another lab procedure already paid for the same patient.
What to do: Check which other lab procedure was paid that day and the laboratory Schedule's rules for that pair.
- Code
- L3
- Description
- Not allowed in addition to other laboratory procedure(s)
Explanation
Updated October 26, 2026
L3 means this lab procedure can't be paid on top of another lab procedure already billed. Check the pairing rules.
What it means
L3 means the laboratory procedure is not payable in addition to another laboratory procedure for the same patient. The other procedure already includes it or excludes it.
Common causes
- Two tests billed together where one includes the other
How to fix it
- Check which other lab procedure was paid for the same patient and date.
- Check the laboratory Schedule's rules for that pair of codes.
- 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 two procedures can't be paid together.
- 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