Modifier RT / LT
HCPCS modifiers identifying procedures performed on the right (RT) or left (LT) side of the body.
1 min read · Last reviewed May 23, 2026
At a glance
- Category
- Billing
- Primary sources
- 1
- Workspace handoff
- denial workbench →
Where this comes up
This shows up in revenue-cycle work — claim scrubbing, charge entry, posting, A/R follow-up, and month-end close. Billers and practice managers hit this term when reconciling a payment, working a denial queue, or auditing why a claim aged past 60 days.
Full definition
What it is in practice
CMS HCPCS recognizes RT and LT for laterality. Some payers prefer RT/LT on separate lines instead of modifier 50; check payer-specific policy.
How it shows up in your practice
Many commercial payers want RT/LT for X-rays and orthopedic procedures even when modifier 50 would apply to Medicare. Build payer-specific macros in the EHR.
Sources
- CMS — Physician Fee Schedule (PFS)https://www.cms.gov/medicare/payment/fee-schedules/physician
Audit laterality denials in the Denial Workbench
Open denial workbench →Related terms
D3rx is a healthcare-billing and compliance research aid maintained by D3rx Inc. Articles are drafted by an LLM (Anthropic Claude) against primary HHS, OCR, CMS, eCFR, NIST, and state-regulator publications, and reviewed for restraint and source fidelity by the D3rx team.
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This glossary entry is a research aid for billing and compliance staff. It does not provide legal, medical, or financial advice and does not replace counsel. References cited link to primary sources at HHS, OCR, CMS, eCFR, NIST, and the relevant payer or industry body.