What is the Difference between a Screening Mammogram and a Diagnostic Mammogram?

What is the difference between a screening mammogram and a diagnostic mammogram? The key distinction lies in their purpose. A screening mammogram is used as a preventive tool for women with no signs or symptoms of breast cancer, while a diagnostic mammogram is performed when there are symptoms or when an abnormality is found during screening.

Regular screening mammograms and clinical breast exams are among the most effective ways to detect breast cancer early. Detecting breast cancer through screening mammography allows treatment to begin sooner—sometimes before the disease spreads.

A screening mammogram is generally the first step in breast cancer detection. It is performed on women who have no current symptoms and are considered at average risk. A diagnostic mammogram, on the other hand, is used when the radiologist or doctor identifies something suspicious during a screening. Both tests use the same imaging machines and technology.

What a Screening Mammogram Involves

A screening mammogram typically consists of four images—two of each breast. The medial lateral oblique (MLO) view captures the breast from the side, while the cranial caudal (CC) view provides an image from the top down.

During review, the radiologist looks for key indicators, including:

• Dense or new axillary lymph nodes

• Asymmetry (when breast tissue appears different from one side to the other)

• Increased calcifications, which may indicate abnormal changes

If any of these findings appear suspicious, the radiologist may request additional images and convert the screening mammogram into a diagnostic mammogram.

When a Diagnostic Mammogram Is Needed

A diagnostic mammogram provides a closer look at specific areas of concern found during screening. These tests capture more detailed X-rays from different angles to help the doctor determine whether the finding requires further evaluation.

In some cases, the technologist magnifies the suspicious area to get a clearer, more detailed view. Diagnostic mammograms are also ordered for women who have symptoms such as a lump, or who experience changes in breast size or shape.

Since 2010, the Affordable Care Act has required all new health insurance plans to fully cover screening mammograms, eliminating out-of-pocket costs for patients. However, diagnostic mammograms may not always be covered in full and could result in additional charges.

Additional Testing and Biopsy

A diagnostic mammogram is often followed by a targeted breast ultrasound to further assess the suspicious area. If imaging reveals an abnormality, the next step is a biopsy, which is the only way to confirm whether cancer cells are present. During a biopsy, a small sample of breast tissue is removed and examined under a microscope.

The BI-RADS System for Mammogram Findings

The American College of Radiology (ACR) developed a standardized classification system called BI-RADS (Breast Imaging Reporting and Data System). This system allows radiologists to describe mammogram results consistently and helps physicians determine appropriate follow-up care.

BI-RADS Categories

• BI-RADS 0: Incomplete—needs additional evaluation

• BI-RADS 1: Negative—routine follow-up in one year

• BI-RADS 2: Benign (non-cancerous) findings—continue regular screening

• BI-RADS 3: Probably benign (less than 5% chance of cancer)—follow-up in six months

• BI-RADS 4: Suspicious abnormality—biopsy may be required

• BI-RADS 5: Highly suggestive of malignancy—biopsy required

• BI-RADS 6: Known, biopsy-proven malignancy

Each category helps doctors make consistent decisions about diagnosis and treatment.

Knowing Which Mammogram You Need

For women without symptoms, a screening mammogram is the best preventive tool for early detection. If an abnormality appears—or if you have symptoms such as a lump, pain, or changes in breast shape—a diagnostic mammogram is recommended for further evaluation.

Understanding the difference between a screening mammogram and a diagnostic mammogram empowers women to take an active role in their health. By knowing when each test is appropriate, patients can make informed decisions, ask better questions, and ensure timely diagnosis and treatment if needed.

Getting Legal Help for Mammogram Misdiagnosis

If your doctor failed to recognize signs of breast cancer or misinterpreted your mammogram results, you may have grounds for a medical malpractice claim. Delayed diagnosis or improper interpretation of imaging can allow cancer to progress unnecessarily, resulting in more invasive treatment and reduced survival rates.

Our firm helps patients and families understand their rights when medical errors lead to harm. If you believe your doctor failed to properly identify your condition or you have questions about the difference between a screening mammogram and a diagnostic mammogram, contact us today. We can review your medical records, consult with specialists, and determine whether negligence played a role in your diagnosis.