If you’ve ever coded a patient chart, you know about the LT (Left side) and RT (Right side) modifiers. Together, the RT and LT modifiers are used to show laterality — in other words, they describe which side of the body was addressed during a procedure or surgery, or if supplies are being prescribed.
Check out a few real-world examples of when the RT and LT modifiers should be used so you’ll be able to collect for claims when the provider addressed both sides of the body or just one.
RT and LT Modifiers For Bilateral Procedures
In some situations, your provider may need to tell payers where on the body they performed a service, as a way to curb denials. While modifier 50 (Bilateral procedure) is often utilized to let an insurer know that you performed the same service on both sides of the body, the RT and LT modifiers can actually provide even more detail.
For instance, suppose you performed a hip injection without ultrasound guidance on the patient’s left hip (20610), and a hip injection with ultrasound guidance on the patient’s right hip (20611). If you bill both procedures on the same claim, you’ll get a denial for 20610, because the Correct Coding Initiative bundles 20610 into 20611. Modifier 50 wouldn’t be accurate since you aren’t reporting the same code for the left and right sides.
Instead, you’ll report 20611-RT on the first line of the claim, and 20610-LT on the second line of the claim form to let the payer know that the services were performed on different hips.
RT and LT Modifiers When Billing Two of the Same Supplies
Although the RT and LT modifiers are frequently thought of as surgical modifiers, most payers require them on supplies in certain situations. For instance, in November 2023, Part B contractor CGS Medicare sent out a “Correct Coding Reminder” to alert practices that it’s essential that they use the RT and LT modifiers “when billing two of the same item or accessory on the same date of service when the items are being used bilaterally.”
For instance, suppose your patient requires two elastic knee orthoses with joints — one for the left knee and one for the right. In this case, you’ll report L1810-LT on one line, followed by L1810-RT on the second line of your claim.
Although some practices might be tempted to use modifier 50 in this case, that’s not considered correct coding, CMS notes. Modifier 50 specifically refers to a bilateral procedure, and supplies are not considered procedures. “When the same code for bilateral items (left and right) is billed on the same date of service, bill each item on two separate claim lines using the RT and LT modifiers and one unit of service (UOS) on each claim line,” the agency says. “Do not use the RTLT modifier on the same claim line and billed with 2 UOS. Claims billed without modifiers RT and/or LT, or with RTLT on the same claim line and 2 UOS, will be rejected as incorrect coding.”
Knowing when to use the right modifier can make or break your claims. Let expert Michael Strong, MSHCA, MBA, CPC, CEMC show you how to use them correctly during his exclusive training event, Master Coding Modifiers and Uncover Unclaimed Revenue. Register today!
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