What is a false-positive finding?

In mammography screening, a false-positive finding is an abnormality in the x-ray, which based on the screening mammogram alone, cannot be clearly classified as benign.

In these cases the woman will be asked to return for a follow-up examination such as an ultrasound. Some women will also require a follow-up - a minimally-invasive biopsy. If this then shows that the abnormality can be classified as benign, it's considered a "false-positive" finding.

False-positive findings aren't "incorrect findings" demonstrating a lack of knowledge or training from mammography screening physicians. Abnormalities should be investigated with additional examinations to prevent “overlooking" breast cancer. A woman will only be diagnosed as having breast cancer if a biopsy confirms the breast cancer suspicion.

Out of 1,000 women examined through the screening, 30 women will be asked to return for a follow-up examination due to an abnormality. Out of these 30 women, 12 will require a biopsy. 6 women will be diagnosed with breast cancer, they have a "positive-positive" mammogram finding and biopsy. So 24 out of 1,000 women will have false-positive findings, and 6 of these women will have had a biopsy.