Radiology Question for the Week of June 30, 2025

Question:

We are still confused about when to use or if to use the LT or RT modifier. Do you have a formula that we could apply based on a scenario?

Answer:

Here is a general formula to follow when trying to decide whether or not to use the LT or RT modifier. Ask the question: “Is this code referring to a procedure done on a body part which is paired?” If the answer is “yes,” then ask: “Is there another modifier which would more specifically describe the procedure being performed?” If the answer is “no,” then select the appropriate modifier to append to the code, depending on which side the procedure is performed. A physician orders a mammogram of the left breast. To correctly report this procedure, append modifier LT to CPT code 77065 (mammography; unilateral). A physician performs a right breast cyst aspiration. To correctly report this procedure, report CPT code 19000 (puncture aspiration of cyst of breast) with modifier RT. If the procedure was performed with ultrasound guidance, also report CPT code 76942. If your third-party payer requires it, assign modifier RT to each code. Note: Code 76942 has a bilateral indicator of “0” on the MPFS, and thus the laterality modifiers and modifier 50 do not apply to the reporting of 76942 to Medicare.

This question was answered in our Breast & Bone Density Procedure Coding Guide. For more hot topics relating to radiology services, please visit our store or call us at 1.800.252.1578, ext. 2.