Additional leukemia-associated markers improve resolution of MRD. Files containing flow cytometric data from 5 nonleukemic BM samples cells (gray dots) and one diagnostic ALL sample (black dots) were merged and analyzed as radial plots using the Kaluza software after selecting all CD19⁺CD10⁺CD34⁺ cells. Mixtures containing 0.01% ALL cells (top row) and 0.001% ALL cells (bottom row) are shown. Underexpression of CD38 alone, a standard MRD marker, could not discriminate well between ALL cells and normal CD19⁺ CD10⁺ CD34⁺ cells (left panels) in this case; the discrimination was improved by analyzing expression of CD97 (middle panels), and further improved by the inclusion of CD86 and the use of a 3-dimensional space (right panels).