Breast Imaging Reporting and Data System (BI-RADS) and Mammogram Results

Scores and What They Mean

The standardized system of reporting breast cancer risk is called the Breast Imaging Reporting and Data System (BI-RADS). It was developed by the American College of Radiology and is a numerical scale ranging from 0 to 6 that is used in mammogram, breast ultrasound, and breast magnetic resonance imaging (MRI) reports. These screening and diagnostic tests help determine your BI-RADS score.

A BI-RADS number reveals to your healthcare providers anything that may look potentially abnormal. It can also help them quantify how concerning the finding is. A change in the number from test to test can also help your healthcare providers more clearly detect a difference between the test results.

This article will explain the BI-RADS classifications and what they mean for your health.

Female doctor talking to her patient and adjusting her position to do a mammogram
andresr / Getty Images

Breast Imaging Reports

A mammogram, a low-energy X-ray examine of the breasts for diagnosis and screening, is the most common breast imaging test. It is often used in breast cancer screening. A breast ultrasound or breast MRI can also help identify breast cancer, and these tests are usually ordered when further evaluation is needed after a mammogram is reviewed.

Breast imaging reports typically consist of a description of your breast density and any abnormalities in your breasts or in the surrounding area. The report will include the size, location, shape, and any other details about a breast mass. It may also be compared to previous images, especially if you have ever had a concerning mass in the past.

One section on your report includes your BI-RADS score, which indicates the radiologist's opinion about the absence or presence of breast cancer. Your score provides details about the possible diagnosis and whether additional testing is necessary.

Your BI-RADS score is part of your mammogram report. It will include information about the density of your breasts and whether there are abnormalities that need further testing. Your healthcare provider can explain your BI-RADS score when they discuss the results of your mammogram.

BI-RADS Classifications and What They Mean

Your BI-RADS score is a number between 0 and 6. Each number corresponds to a classification that estimates your breast cancer risk based on the imaging test.

Category Diagnosis Number of Criteria
0 Incomplete Your mammogram or ultrasound didn't give the radiologist enough information to make a clear diagnosis; follow-up imaging is necessary.
1 Negative There is nothing to comment on; routine screening is recommended.
2 Benign A definite benign finding; routine screening is recommended.
3 Probably benign Findings have a high probability of being benign, or noncancerous (>98%); six-month follow-up is recommended.
4 Suspicious abnormality Finding is not characteristic of breast cancer, but there is a possibility of malignancy, or cancer (3%–94%); biopsy should be considered.
5 Highly suspicious of malignancy Lesion that has a high probability of being malignant (>= 95%) is detected; take appropriate action as recommended by your healthcare provider.
6 Known biopsy proven malignancy Lesions known to be malignant are being imaged prior to definitive treatment; assure that treatment is completed.

Category 0: Incomplete

A score of 0 means that your mammogram or ultrasound didn't provide enough information for a clear diagnosis. This does not necessarily mean your healthcare provider is worried about breast cancer.

This designation requires a follow-up imaging study, such as a mammogram or ultrasound obtained with special views, or a breast MRI. Your report may be classified with a 0 rating if a palpable breast lump isn't imaging clearly, if scar tissue from a previous biopsy or surgery is interfering with the image, or if your breasts are dense.

Category 1: Normal

A score of 1 means that you do not have any suspicious masses or calcifications and your breast tissue looks healthy.

Category 2: Benign

A score of 2 is given when your breast tissue looks normal and any cysts, fibroadenomas (noncancerous tumors), or other masses appear benign.

A score of 1 or 2 does not mean that you are not at risk for breast cancer or could not have breast cancer. If your mammogram score falls into one of these categories, it is still important to continue regularly scheduled breast exams and mammograms.

Category 3: Probably Benign

A score of 3 refers to a finding of uncertain significance. Short-term follow-up is ordered to make sure that the finding remains stable.

Category 4: Possibly Malignant

A score of 4 is reported when there are one or more suspicious lesions, masses, or calcifications. A breast biopsy is often recommended to check the suspicious area.

Category 5: Malignant

A score of 5 means that there is a mass (or more than one mass) with an appearance of cancer. A biopsy is recommended to make an accurate diagnosis.

It's important to note that even though this category is described as "malignant," masses may appear cancerous but are related to a benign condition instead. Conditions such as adenosis, fat necrosis, radial scars, and mastitis can sometimes look like cancer on a mammogram.

Category 6: Malignant Tissue

Category 6 is only used if tissue from a biopsy has been examined and found to be cancerous. If this is the case, treatment is necessary. This can include surgery, chemotherapy, and/or radiation. The imaging test is being obtained as part of the treatment or follow-up plan.

BI-RADS Scoring and Breast Density

BI-RADS reports also score breast density, which assesses how much fatty, glandular, and fibrous tissue you have in your breasts. Dense breast tissue can make it harder to spot tumors on your mammogram.

BI-RADS scoring uses four levels of density:

  • Almost all fatty tissue (easiest to see anomalies or tumors)
  • Scattered areas of dense (fibrous and glandular) tissue, but mostly fatty tissue
  • Mix of dense and fatty tissue
  • Mostly dense tissue (hardest to see tumors)

Limitations of BI-RADS

For younger women, children, and adolescents, the BI-RADS score may not be reliable.

It's also important to note that your BI-RADS score doesn't replace the opinion and insight of your healthcare provider or radiologist regarding your imaging tests. The number is not a substitute for a clinical exam.


Your BI-RADS score is there to help your doctor discuss your breast cancer risk with you and what your results mean. The score also allows your healthcare provider to compare results over time and determine whether additional, definitive testing is necessary. It does not replace a thoughtful analysis by a radiologist or a clinical exam, and it may not be reliable for everyone.

Talk with your healthcare provider about your BI-RADS score and what it means for your health and future screenings or treatment.

A Word From Verywell

Some breast images do not fit neatly into BI-RADS categories, and there may be a wide variety of findings even within the categories. While you may want to quickly find your BI-RADS number to make a conclusion about your health, it is important that you discuss your results with your healthcare provider—even if your breast imaging test turns out negative.

Screening mammograms are considered the most effective way to identify early-stage breast cancer and to get the most timely and definitive treatment. It is important to follow the guidelines for recommended screening tests, and follow-up tests if recommended. The BI-RADS score is a useful way to compare and standardize breast imaging studies. Just remember that it is only one of the many tools that your medical team uses to assess your health.

Frequently Asked Questions

  • What does it mean when BI-RADS category 4 is suspicious?

    In BI-RADS category 4, the word "suspicious" is used to address the possibility that cancer may be present. BI-RADS category 4 is separated into three sub-categories:

    • 4A: Low likelihood of cancer, between two and 10 percent
    • 4B: Potential cancer, between 10 and 50 percent
    • 4C: Greater likelihood of cancer, between 50 and 95 percent
  • What is the meaning of probably benign or malignant findings?

    A BI-RADS score of 3, or "probably benign" means that there is something of uncertain significance on your mammogram, but that it is most likely not cancer. A follow-up mammogram may be recommended in a few months afterward. Malignant—or "probably malignant"—findings indicate that you will probably need a biopsy. This type of test involves taking a sample of tissue and looking at it more closely under a microscope to see if cancer is present.

3 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Park GE, Kim SH, Lee JM, Kang BJ, Chae BJ. Comparison of positive predictive values of categorization of suspicious calcifications using the 4th and 5th editions of BI-RADS. AJR Am J Roentgenol. 2019;213:710-715. doi:10.2214/AJR.18.20866

  2. American Cancer Society. Understanding Your Mammogram Report.

  3. American Cancer Society. Breast Density and Your Mammogram Report.

Additional Reading
Originally written by Pam Stephan
Pam Stephan is a breast cancer survivor.
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