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Guide to Lymphoid Neoplasia Testing


Which test should be submitted? The answer to this depends on the clinical signs, and the diagnostic question you are asking. If you already have a cytologic or histologic diagnosis of lymphoma and are confident in this diagnosis, the only reason to submit additional testing is for prognostic information based on phenotype, or if treatment is going to be guided by phenotype.

If cytology or histology give equivocal results, and/or you are seeking additional prognostic or diagnostic information, use the guidelines below to choose a test, or feel free to call the laboratory at 970-491-1170 or email at

Click on the link for each test to find out how to submit a sample.
​Species ​Clinical Sign ​Site ​Cytology/Histology ​Best Test to Submit
​Dog/Cat ​Lymphocytosis ​Peripheral Blood ​Small mature lymphocytes Flow Cytometry
Dog​ Lymphocytosis​ Peripheral Blood ​Immature forms/blasts Flow Cytometry​​
Cat​ Lymphocytosis​ Peripheral Blood​ Immature forms/blasts​ Flow Cytometry / Immunocytochemistry
Dog/Cat​ ​Normal WBC ​Peripheral Blood ​Immature forms/blasts Please call laboratory.
Dog/Cat​ Lymphadenopathy​ Lymph node aspirate​ Confirmed or strongly suspicious for lymphoma​ Flow Cytometry​​
Dog/Cat​ Lymphadenopathy​ Lymph node aspirate​ Homogeneous population of small lymphocytes​ Flow Cytometry​​
Dog/Cat​ Lymphadenopathy​ Lymph node aspirate​ Heterogeneous or reactive with rare suspicious cells​ PARR
Dog/Cat​ Organomegaly​ ​Aspirate of organ ​Same rules as lymphadenopathy ​Same rules as lymphadenopathy.
Dog/Cat​ ​Cavity effusion ​Pleural/peritoneal fluid A large number of abnormal lymphoid cells/large number of small mature cells​ Flow Cytometry
​Dog/Cat Mediastinal mass​ ​Mediastinum Suspicious for either lymphoma or thymoma​ Flow Cytometry is the best way to distinguish between these two entities​.
​Dog/Cat ​Cavity effusion ​Pleural/peritoneal fluid ​Rare abnormal lymphoid cells PARR
​Dog/Cat GI Disease​ ​Mesenteric lymph node ​Reactive or neoplastic PARR
​Dog/Cat ​CSF ​CSF ​Elevated WBC consisting of normal or abnormal lymphocytes PARR
​Dog ​Leukopenia ​Bone marrow ​Blasts present Flow Cytometry​​​
​Dog/Cat ​Leukopenia ​Bone marrow ​Small lymphocytes present Flow Cytometry​​ (peripheral blood is better if there is lymphocytosis)
​Cat ​Leukopenia ​Bone marrow ​Blasts present Immunocytochemistry
​Dog/Cat Leukopenia​ Bone marrow​ ​No clearly neoplastic cells PARR
​Dog/Cat ​Hyperglobulinemia ​Serum ​Immunofixation
​Dog/Cat ​Neutrophilia We cannot diagnose chronic myelogenous leukemia by flow or PARR​.
​Dog/Cat Hypercalcemia​ Testing blood or other aspirates in cases where the only sign is hypercalcemia is generally unrewarding​.
​Dog/Cat ​Screening, no clinical signs We do not recommend either PARR or flow cytometry to be used as a screening test in a healthy animal with no clinical signs​.