Choose a test


For dogs, immunophenotyping by flow cytometry is almost always the test of choice because it can provide both a diagnosis and prognostic information. Flow cytometry can be more sensitive and less invasive than histology for detecting emerging lymphoid neoplasia. There are some forms of lymphoma, however, that require histology for subtyping and prognosis.


Cats more often have non‐neoplastic lymphocyte expansions in the blood and other organs, and fewer antibodies are available for immunophenotyping. In feline cases of lymphocytosis, flow cytometry of peripheral blood can sometimes provide prognostic information. In feline solid organs, however, PARR may be more useful for an affirmative diagnosis of lymphoma. A combination of histology and immunohistochemistry/PARR may be more useful than flow cytometry.

Guide to testing for hematopoietic malignancy

Use the guidelines below to choose a test. Some cases may require a combination of tests for definitive diagnosis and prognostic information. No diagnostic test can ever completely rule out cancer.

SpeciesClinical signSiteFirst test to submitNotes
DogCytologically suspicious or confirmed neoplastic lymphocytes in any tissue (solid organs, bone marrow, blood,
Affected organFlow cytometryDo not submit blood when there is no lymphocytosis or cytologically suspicious cells in the blood.
DogDifferentiating thymoma from lymphoma.MediastinumFlow cytometry
DogExpanded population of lymphocytes in the peripheral blood that are cytologically normal.Peripheral bloodFlow cytometry
DogEnlarged lymph nodes/spleen with lymphocytes described as cytologically normal.Affected organFlow cytometry
DogNeurologic signs with significantly elevated white count in the CSF.CSFPARRA minimum of 50,000 cells are needed for a diagnostic PARR result.
DogFlow cytometry results were equivocal.PARRDo not collect a new sample. PARR can be performed on the sample already submitted for flow cytometry.
DogFlow cytometry showed B cell chronic lymphocytic leukemia; looking for additional prognostic information.Peripheral bloodKi67Ki67 expression indicates proliferation and is prognostic in B cell CLL.
DogHistologically suspicious cells in a lymphocyte-rich biopsy.Request curls from the biopsy block.PARR
DogHistology suspicious but not definitive for lymphoma.Affected organPARR on the biopsy block or flow cytometry of a fresh aspirate.In cases where a precursor neoplasm is suspected (acute leukemia, which can also present with primarily solid organ involvement) flow cytometry of a fresh aspirate is preferred.
CatLymphocytosisPeripheral bloodFlow cytometryFlow cytometry can be diagnostic and prognostic, but many cases require follow-up PARR testing. If a myeloid, erythroid or acute leukemia is suspected, flow cytometry is not useful.
CatCytologically confirmed neoplastic lymphocytes in any tissue.Affected organFlow cytometry
CatCytologically suspicious cells in any tissue or
expansion of small lymphocytes.
Affected organPARR
CatEquivocal evidence of neoplastic lymphocytes in a formalin‐fixed biopsy.Request curls from the biopsy block.PARR
Dog or CatWanting to determine if plasma cells are neoplastic.AnyPARRWe do not have antibodies to identify plasma cell by flow cytometry.
Dog or CatSuspicion for neutrophilic leukemia (CML) or eosinophilic leukemia.BloodNoneWe cannot distinguish neoplastic from reactive neutrophils or eosinophils by any currently available testing.

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Additional Testing at CSU

Additional testing offered through the CSU Veterinary Diagnostic Laboratory may help with the diagnosis of a suspected hematopoietic disease.

TestPrice Information
Complete blood countCSU Veterinary Diagnostic Laboratories Test Information
CytologyCSU Veterinary Diagnostic Laboratories Test Information
Protein electrophoresis and immunofixationCSU Veterinary Diagnostic Laboratories Test Information