Current Procedural Terminology (CPT) codes are a standardized system used by healthcare providers and insurance companies to describe medical services and procedures. This coding language ensures uniformity in documentation and communication about the care a patient receives. Understanding the specific code assigned to a procedure is important for patients because it directly impacts billing, insurance coverage, and out-of-pocket costs.
The Specific Meaning of CPT 77066
CPT code 77066 officially describes a “Diagnostic mammography, including computer-aided detection (CAD) when performed; bilateral.” This code reports a detailed X-ray examination of both breasts to investigate a specific clinical concern. The term “bilateral” indicates that the procedure involves imaging both the right and left breast. The corresponding code for a single breast examination is CPT 77065, designated as “unilateral.”
The primary modifier, “Diagnostic,” signifies that the procedure is not a routine check but an investigative step prompted by a medical finding or symptom. This is distinct from a preventative screening. The inclusion of “Computer-Aided Detection (CAD)” means that specialized software is used to analyze the digital images.
CAD technology acts as a “second look” for the radiologist, highlighting areas on the mammogram that may represent subtle signs of abnormality. The software detects features like microcalcifications, masses, or areas of tissue asymmetry. The radiologist reviews the CAD markings alongside the original images to determine if the highlighted areas require further evaluation.
CAD’s primary role is to assist the human interpreter, not replace them, ensuring a comprehensive evaluation of the breast tissue. The entire procedure, including the detailed imaging and the computer analysis, is encapsulated within the single code 77066.
Diagnostic Versus Screening Mammography
The fundamental difference between diagnostic and screening mammography lies in the patient’s health status and the examination’s purpose. Screening mammography is a routine preventative procedure performed on asymptomatic patients who have no signs or symptoms of breast disease. The goal of screening is to detect cancer early before it becomes palpable or causes noticeable symptoms.
Screening mammograms are typically assigned CPT code 77067. Because they are preventative, they are often covered fully by insurance under the Affordable Care Act for women over 40.
In contrast, a diagnostic mammogram (CPT 77066) is performed on a patient who is symptomatic or has a previously identified abnormality requiring investigation. This procedure is focused, using specialized techniques like spot compression or magnification views to closely examine a specific area of concern. The radiologist is often present during the procedure to guide the additional imaging.
Diagnostic examinations are generally considered a treatment or follow-up service, not a preventative one. This difference in classification means diagnostic mammograms are typically subject to patient cost-sharing, such as deductibles and co-pays, unlike routine screenings. The change in the examination’s purpose dictates the use of the diagnostic code 77066 instead of the screening code 77067.
Situations Requiring a Diagnostic Mammogram
A physician orders a diagnostic mammogram (CPT 77066) when there is a clear medical indication requiring a detailed investigation of the breast tissue. One of the most common triggers is the presence of a new palpable breast lump or mass discovered by the patient or a clinician. Any new lump should be evaluated with a diagnostic mammogram and often an accompanying ultrasound.
Other clinical signs that necessitate this procedure include symptoms such as focal breast pain or spontaneous nipple discharge. New changes to the nipple, such as inversion, or alterations in the skin texture of the breast are also indications for a diagnostic study. These symptoms signal a need to focus imaging on the affected area to determine the underlying cause.
The diagnostic mammogram is also required as a follow-up to an abnormal screening result. If a routine screening identifies a suspicious finding, the patient is called back for a diagnostic study to obtain additional, detailed images of that area. This detailed imaging is also used for short-term follow-up of findings that are likely benign but still require close monitoring.
Patients with a personal history of breast cancer often receive annual surveillance via diagnostic mammogram, even if they are currently asymptomatic. Furthermore, assessing breast implants for rupture or evaluating the surrounding tissue typically requires the specialized views and techniques of a diagnostic mammogram, justifying the use of CPT 77066.