Shields Index values scatterplot. The Shields Index values, for all 106 patients assessed, were plotted on a scatterplot to represent the spread in Shields Index values for the metastatic and non-metastatic groups. The Shields Index (calculated from epi-tumoural LD, lymphatic vessel invasion and Breslow thickness). With a cut off point of 2.10, 92 of the 106 samples are correctly predicted (86.8%) with only 14 samples predicting incorrectly. A total of 5 patients that later developed metastases were predicted to be non-metastatic and 9 patients that have not yet developed metastases are predicted to do so.