As with any medical test, mammography has limitations. The limitations of mammograms are:
Mammograms are only part of a complete breast exam. If mammograms show abnormalities your healthcare provider will follow-up with other tests.
False negatives can happen. This means everything may look normal, but cancer is actually present. False negatives don't happen often. Younger women are more likely to have a false negative mammogram than are older women. This is because breast tissue of younger women is denser, making cancer harder to spot.
False positives can happen. This occurs when the mammogram results look like cancer is present, even though it is not. False positives are more common in younger women than older women.