Modifiers · HCPCS modifier

Right side

Modifier RT is a two-character HCPCS modifier appended to a procedure or supply code to specify that the service was performed on the right side of the body. It is paired with modifier LT (left side) and is required by Medicare and most payers whenever a code describes a procedure that can be anatomically distinguished as either left or right. It carries no standalone reimbursement value but is essential for accurate claims adjudication.

Verified May 8, 2026 · 9 sources ↓

Type: HCPCS
CPT codes use it: 1,527
Top regions: Foot & ankle, Hand, Wrist

Drawn from CMSCgsmedicareEmblemhealthMedicareproviderAAOS

When to use modifier RT

Source · Editorial brief grounded in 9 cited references ↓

Append modifier RT whenever you bill a CPT or HCPCS code for a procedure or item that is anatomically lateralizable and performed exclusively on the right side of the body. Medicare's CMS Article A56869 identifies specific codes where RT is mandatory—submitting those codes without a laterality modifier will result in automatic claim rejection, not a simple denial. This applies across surgical, diagnostic, and durable medical equipment contexts, from a right total knee arthroplasty to a right orthotic shoe insert.

When the same procedure is performed on both sides in the same operative session and the code carries a Bilateral Surgery Indicator of 1, use modifier 50 on a single claim line instead of separate RT and LT lines. CMS Pub. 100-04 is explicit: RT and LT must not appear on the same claim line alongside modifier 50, and doing so will cause the claim to be returned to the provider. However, if the bilateral indicator is 3 (no 150% adjustment), modifier 50 still applies on one line—RT and LT remain inappropriate there as well.

For DME suppliers, CGS Medicare guidance specifies that when two of the same item are dispensed bilaterally—for example, bilateral wrist splints—each item must be billed on a separate claim line: one line with RT and one with LT, each with one unit of service. Never combine RT and LT on a single claim line with two units; that construct will be rejected as incorrect coding.

Orthopedic scenarios

Concrete situations in orthopedic practice that warrant modifier RT.

Source · Editorial brief grounded in AAOS coding guidance and cited references ↓

Right total knee arthroplasty (CPT 27447): append RT to distinguish the right knee from a prior or concurrent left-side claim and prevent duplicate-claim rejection.
Right knee diagnostic arthroscopy (CPT 29870): bill with modifier RT when only the right knee is scoped; omitting it when the left was previously scoped in the same episode risks an automatic duplicate flag.
Right distal radius ORIF (CPT 25600 or 25605): RT documents that the fracture fixation was performed on the right wrist, which is critical when bilateral wrist fractures are treated in staged procedures.
Right shoulder rotator cuff repair (CPT 23412 or 29827): RT is required so payers can distinguish a right-side repair from any subsequent or prior left-shoulder claim for the same patient.
Right hip hemiarthroplasty (CPT 27125): append RT to confirm the operative side, particularly relevant when the contralateral hip may be addressed in a future admission.
Right ankle ORIF for bimalleolar fracture (CPT 27769): RT clarifies side of service and prevents denial when the patient has a history of left ankle surgery billed under the same CPT code.
Right knee medial meniscectomy via arthroscopy (CPT 29881): RT is mandatory per CMS Article A56869 for arthroscopic knee codes to avoid rejection as a duplicate or unspecified-laterality claim.

Common mistakes

Where coders most often go wrong with modifier RT.

Source · Editorial brief grounded in CMS NCCI Policy Manual and cited references ↓

Appending RT on the same claim line as modifier 50 for a bilateral procedure with payment indicator 1—CMS will return the claim to the provider.
Omitting RT entirely on a code listed in CMS Article A56869, which triggers automatic rejection rather than a reviewable denial.
Using RT on a procedure code whose CPT descriptor already specifies 'bilateral' or 'unilateral or bilateral'—the code is inclusive of both sides and RT is neither required nor appropriate.
Placing RT and LT on the same single claim line with two units of service for DME items—each side must occupy its own separate claim line with one unit each.
Mixing modifier 50 and modifier RT on the same procedure code within one claim, which constitutes conflicting modifier logic and will be rejected under NCCI edits.
Failing to apply RT to a right-sided unilateral procedure when the same code was previously billed for the left side—payers flag the second submission as a duplicate unless laterality is explicit.
Applying RT to midline structures such as the bladder, uterus, or nasal septum where laterality is not anatomically meaningful and modifier 50 rules do not apply.

CPT codes that use modifier RT

1,527 orthopedic CPT codes in our reference list this modifier as applicable. Sorted by total RVU.

Source · Derived from per-code modifier guidance in our CPT reference

Showing top 12 of 1,527 by total RVU.

Where modifier RT shows up

Body regions where this modifier most commonly appears in our orthopedic reference.

Foot & ankle 335 codes
Hand 207 codes
Wrist 165 codes
Knee 164 codes

Frequently asked questions

Source · Generated from the editorial pipeline, verified against 9 cited references ↓

01Does modifier RT change how much I get paid?

No—RT is an informational modifier and does not increase or decrease the allowed amount. Its function is to route the claim correctly and prevent duplicate-claim rejections; reimbursement remains at 100% of the fee schedule or contracted rate for the underlying procedure code.

02Can I use RT and modifier 50 together on the same claim line?

No. CMS Pub. 100-04 explicitly prohibits combining RT (or LT) with modifier 50 on the same claim line for procedures with a bilateral payment indicator of 1. Doing so will cause the claim to be returned to the provider. Use modifier 50 alone on a single line item for qualifying bilateral procedures.

03What happens if I forget to add RT to a required code?

For codes listed in CMS Article A56869, omitting RT results in automatic claim rejection—not a standard denial. This means the claim will not enter the adjudication queue at all and must be corrected and resubmitted with the appropriate laterality modifier.

04Should RT be used for procedures on midline structures like the spine or bladder?

Generally no. Midline organs such as the bladder, uterus, esophagus, and nasal septum are not anatomically lateralizable, so RT is not applicable. For spinal procedures, laterality is typically captured through specific CPT code selection rather than RT/LT modifiers; confirm requirements with the individual payer.

05How do I bill the same procedure performed on both knees on the same day?

If the CPT code has a bilateral payment indicator of 1 (e.g., CPT 27447), report it once with modifier 50 on a single claim line—do not use RT and LT separately. If the bilateral indicator is 3, still use modifier 50 on one line. Check the payer's specific policy, as some non-Medicare payers prefer separate RT and LT lines.

06Do DME suppliers use RT differently than physicians?

For DME, when two identical items are dispensed bilaterally, CGS Medicare guidance requires one claim line with RT (one unit) and a separate claim line with LT (one unit). Combining both modifiers on a single line with two units of service will be rejected as incorrect coding.

07Is modifier RT required for every right-sided procedure, or only specific codes?

RT is required specifically for codes that CMS and payers have identified as lateralizable. CMS Article A56869 lists codes that will be rejected without a laterality modifier. For codes not on that list, RT is still best practice for clarity and duplicate-claim prevention, but the rejection risk is code-specific—review the applicable LCD and payer policy.

Sources & references

Editorial content was developed using the following public sources. Last verified May 8, 2026.

01
cms.gov
https://www.cms.gov/medicare-coverage-database/view/article.aspx?articleId=56869
02
cms.gov
https://www.cms.gov/Regulations-and-Guidance/Guidance/Transmittals/downloads/R1777CP.pdf
03
cgsmedicare.com
https://www.cgsmedicare.com/jc/education/fact_sheets/bilateral_modifiers.html
04
emblemhealth.com
https://www.emblemhealth.com/providers/claims-corner/coding/correct-usage-of-modifier-50-and-modifiers-lt-and-rt-for-bilater
05
medicareprovider.healthybluemo.com
https://medicareprovider.healthybluemo.com/docs/gpp/MOCARE_LT_RT_Coding.pdf
06
aaos.org
https://www.aaos.org/globalassets/quality-and-practice-resources/coding-and-reimbursement/resident-guide/resident-guide_modifiers.pdf
07
coa.org
https://coa.org/docs/2012-Annual-Meeting/EllisStephaniePresentation.pdf
08CMS NCCI Policy Manual, Chapter 1 (General Correct Coding Policies)
09AMA CPT Modifier guidance — modifier RT descriptor and usage notes

Mira AI Scribe

When the operative note or clinical documentation clearly identifies a procedure performed on the right side of the body—such as a right knee arthroscopy, right shoulder repair, or right hip arthroplasty—the AI scribe should flag the associated CPT or HCPCS code for modifier RT. RT is a two-character HCPCS laterality modifier required by Medicare and most commercial payers to distinguish right-sided from left-sided services. It prevents duplicate-claim rejections and ensures accurate adjudication. RT should not be suggested when the procedure code description already includes 'bilateral' or 'unilateral or bilateral,' or when modifier 50 applies to a same-session bilateral procedure. The scribe should not combine RT and LT on a single line item.

See how Mira flags modifier RT in dictation