Diagnostic mammogram: An X-ray of the breast done to evaluate:

• Abnormalities seen or suspected on a prior screening mammogram;
• Subjective or objectives abnormalities in the breast such as a lump, pain, thickening, nipple discharge or a inexplicable change in breast size or shape;
• Breasts for which it is difficult to obtain a clear X-ray by a screening mammogram because of special circumstances such as breast implants.

A diagnostic mammogram takes longer and involves correspondingly more radiation exposure than a screening mammogram because it involves more X-rays.