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

Abstract

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.