Identification of neoplastic cells in blood using the Sysmex XT-2000iV: a preliminary step in the diagnosis of canine leukemia

Background Classification of leukemias requires specialized diagnostic techniques. Automated preliminary indicators of neoplastic cells in blood would expedite selection of appropriate tests. Objective The objective of this study was to assess the capacity of the Sysmex XT-2000iV hematology analyzer to identify neoplastic cells in canine blood samples. Methods Blood samples (n=160) were grouped into 5 categories: acute leukemia (n=30), chronic leukemia (n=15), neoplasia without blood involvement (n=41), non-neoplastic reactive conditions (n=31), and healthy dogs (n=43). WBC counts, WBC flags, scattergrams, percentages of cells with high fluorescence intensity, and percentages of cells in the lysis-resistant region were evaluated alone or in combination to establish a "leukemic flag." Sensitivity, specificity, negative (LR-) and positive (LR+) likelihood ratios, and the number of false-negative (FN) and false-positive (FP) results were calculated, and receiver operating characteristic curves were designed for numerical values. Results Among single measurements and parameters, only the evaluation of scattergrams minimized FN and FP results (sensitivity 100%, specificity 94.8%, LR+ 19.17, and LR- 0.00), although their interpretation was subjective. The more objective approach based on the generation of a "leukemic flag" had a sensitivity of 100%, specificity of 87.0%, LR- of 0.00, and LR+ of 7.67. Conclusion Using a novel gating strategy the Sysmex XT-2000iV may be used effectively to screen canine blood for hematopoietic neoplasia.