GY modifier: Statutorily excluded service
Category: Modifier
By Dr. Daniel Turner, DC · Reviewed September 2, 2026
What is GY modifier used for?
The modifier stating a service is excluded from Medicare coverage by statute, so no coverage decision is being requested: the claim exists to generate a formal denial, usually so a secondary payer or the patient billing process can proceed.
How it works in a chiropractic practice
Everything a chiropractor does except spinal CMT is statutorily excluded from Medicare: exams, X-rays, therapies, extraspinal work. GY is how those services are billed when a denial on the record is needed, most often because the patient has secondary insurance that pays after Medicare formally declines. The denial arrives as patient responsibility, the secondary payer sees it, and the claim moves on.
What the note must show
- ✓No ABN is required for statutorily excluded services, though the voluntary GX notice is available as a courtesy
- ✓GY rides the excluded lines: the E/M code, the therapy codes, extraspinal CMT
- ✓The spinal CMT line keeps its own AT or GA logic; GY never belongs on covered spinal manipulation
A worked example
A Medicare patient with a paying secondary plan gets an exam and an adjustment. The claim carries the E/M with GY and the CMT with AT. Medicare pays the CMT, denies the exam to patient responsibility as excluded, and the secondary picks up the exam per its own rules. Without the exam on the claim at all, the secondary has nothing to adjudicate.
Does Medicare pay chiropractors for GY modifier?
Grounded in the statutory limitation that Medicare covers chiropractors only for manual manipulation of the spine to correct a subluxation. Everything else is excluded regardless of documentation, which is exactly what GY asserts.
Where practices get burned
Using GA where GY belongs and vice versa; leaving excluded services off claims entirely when a secondary payer needs the denial; expecting Medicare to pay a GY line.
How Cervica helps with GY modifier
Cervica's claim scrubber validates modifiers, units, and diagnosis pointers for GY modifier before submission, per payer rules handle code substitutions and modifier requirements automatically, and when a payer pushes back anyway the denial worklist reads the adjustment codes and routes the claim to the exact fix.
Related codes
- →GA modifier · Waiver of liability statement on file
- →AT modifier · Active treatment modifier for Medicare CMT
- →98943 · Chiropractic manipulative treatment, extraspinal
- →PR-96 · the denial this code most often triggers
- →PR-170 / CO-170 · the denial this code most often triggers
Quick answers
What is GY modifier used for?
The modifier stating a service is excluded from Medicare coverage by statute, so no coverage decision is being requested: the claim exists to generate a formal denial, usually so a secondary payer or the patient billing process can proceed.
What documentation does GY modifier require?
No ABN is required for statutorily excluded services, though the voluntary GX notice is available as a courtesy GY rides the excluded lines: the E/M code, the therapy codes, extraspinal CMT The spinal CMT line keeps its own AT or GA logic; GY never belongs on covered spinal manipulation
Does Medicare pay chiropractors for GY modifier?
Grounded in the statutory limitation that Medicare covers chiropractors only for manual manipulation of the spine to correct a subluxation. Everything else is excluded regardless of documentation, which is exactly what GY asserts.
References
General information for billing teams, not legal, coding, or payer specific advice. CPT is a registered trademark of the American Medical Association; code descriptions here are paraphrased in our own words and the AMA's CPT publications control. Payer policies vary and control for any individual claim.