Current Procedural Terminology (CPT) codes are the standardized language used to describe medical services and procedures for billing and reimbursement. These codes provide a uniform way for healthcare providers and payers to communicate about the services a patient receives. For a common imaging procedure like a bilateral breast ultrasound, identifying the correct code and understanding its context is necessary for accurate claims submission and coverage.
The Specific CPT Code for Breast Ultrasound
The core CPT code for a comprehensive breast ultrasound is 76641: “Ultrasound, breast, unilateral, real time with image documentation, including axilla when performed; complete.” This code represents the standard for a comprehensive unilateral evaluation. A complete study must include the entire breast structure, encompassing all four quadrants and the retroareolar region. The code itself is strictly unilateral, meaning it represents the work performed on a single breast. When a comprehensive ultrasound is performed on both breasts, the billing process uses the unilateral code 76641 in conjunction with a specific modifier to indicate the bilateral nature of the exam.
The Difference Between Diagnostic and Screening Uses
The CPT code 76641 is used for both diagnostic and screening breast ultrasounds, but the distinction is made through the accompanying ICD-10 diagnosis codes. A diagnostic ultrasound is performed when a patient presents with symptoms, such as a palpable lump, pain, or nipple discharge, or when following up on an abnormality detected on a mammogram. Medical necessity is reflected by ICD-10 codes describing the patient’s symptom or condition.
A screening ultrasound, in contrast, is performed on an asymptomatic patient considered high-risk for breast cancer, often due to dense breast tissue or a strong family history. Screening necessity is supported by specific ICD-10 codes, such as Z codes or R92.3. The intent of the study determines the classification, which significantly impacts insurance coverage and reimbursement. Payers often have different policies for covering diagnostic versus screening procedures.
Billing for Symmetry Modifiers
The bilateral nature of a breast ultrasound is communicated using specific symmetry modifiers appended to the unilateral CPT code 76641. The most common method involves appending Modifier -50, which signifies a bilateral procedure. When Modifier -50 is used, the code is typically listed only once on the claim form. For example, Medicare often reimburses at 150% of the single-breast rate to account for the work involved in examining both sides.
Payer rules can vary widely, however. Some commercial insurance plans may require the unilateral CPT code to be listed on two separate lines. In this alternative method, anatomical modifiers are used: RT (Right side) on one line and LT (Left side) on the second line. Healthcare providers must verify the specific billing requirements of each major payer to ensure correct claim processing.
Alternatives to the Bilateral Complete Study
Not every breast ultrasound qualifies for the complete study code 76641, even when performed bilaterally, and miscoding can result in claim denials. The “limited” study code, 76642, should be used for a targeted evaluation focused on a specific area, such as assessing a single known cyst or mass. This limited examination does not involve the full survey of all four quadrants and the retroareolar region required for the complete study code.
When only one breast is examined, the procedure is inherently unilateral, and the appropriate code (76641 for complete or 76642 for limited) is billed without the -50 modifier. If a patient requires a complete ultrasound of the left breast and only a limited, focused ultrasound of the right breast, the claim must be billed using both codes with their respective lateral modifiers, such as 76641-LT and 76642-RT.
It is also important to distinguish between purely diagnostic or screening ultrasounds and interventional procedures that utilize ultrasound guidance. Procedures like a breast biopsy, aspiration of a cyst, or placement of a localization device are billed using a separate series of CPT codes, often in the 19000-series.
For example, an ultrasound-guided breast biopsy is billed using code 19083, which inherently includes the guidance component. These interventional codes should not be confused with the standalone diagnostic codes 76641 or 76642, which describe the imaging study itself. Diagnostic ultrasound may only be billed separately if it occurs at a distinct session from the interventional procedure and is necessary to confirm the need for the intervention.