Identification of peripheral blood involvement in dogs with large B-cell lymphoma: Comparison of different methods.

Stage V lymphoma is defined as the presence of neoplastic cells in peripheral blood (PB), bone marrow, or any other non-lymphoid tissue. Still, official guidelines do not specify which technique should be used to assess infiltration. We assessed the agreement among flow cytometry (FC), blood smear evaluation, and ADVIA120 (LUC and BASO) to quantify PB infiltration in 100 dogs with large B-cell lymphoma (LBCL). Significant errors were found for all methods compared to FC. A moderate agreement was present between FC and blood smear evaluation, whereas LUC and BASO had excellent specificity but unsatisfactory sensitivity in detecting FC infiltrated PB samples. The different techniques should not be used alternatively. We support the use of LUC/BASO as a speedy preliminary test to detect infiltrated samples, and the joined use of blood smear evaluation and FC to quantify definitively the infiltration. Our results are valid only within canine LBCL staging workup, once the diagnosis has been confirmed.