February 2026
In this VETgirl online veterinary continuing education blog, Drs. Christine Mullin, DACVIM (Oncology) and Craig Clifford, DACVIM (Oncology), share practical, real-world strategies for primary care veterinarians to advance their oncologic workups. From staging and immunophenotyping lymphoma to integrating innovative, noninvasive screening tools, discover actionable diagnostic steps that streamline patient care, reduce client costs, and strengthen collaboration with your local oncologist to best support cancer patients before referral.

Oncology Diagnostics for the Primary Care Veterinarian: How to Prepare Your Patient for Referral

By Drs. Christine Mullin, DACVIM (Oncology) & Craig A. Clifford, MS, DACVIM (Oncology), BluePearl Malvern, Malvern, PA

Introduction

The average cost for a routine veterinary visit in the United States can range from $70 to $174 for dogs and $53 to $124 for cats.1 The financial burden can increase exponentially for a sick visit, particularly when a cancer is discovered or suspected. A considerable portion of the expense incurred by an owner of a veterinary cancer patient lies in the diagnostic workup, much of which is traditionally performed at referral institutions. In order to free up client financial resources and potentially increase client access to specialty oncology care, the primary care veterinarian could play a more significant role in the diagnostic workup of these patients. Below, we outline some of the diagnostic tools available in everyday practice that can help streamline oncology care for our veterinary patients, all while promoting a more active and ongoing role of the primary care vet in that patient’s cancer journey.

General Cancer Patient Workup

Upon diagnosis or suspicion of a cancer, a few basic tests could be performed in primary care practice to not only expedite the staging process but also provide general insight into that pet’s overall health. Whether evaluating a patient confirmed or suspected to have a systemic cancer, like lymphoma, or one that has been diagnosed with a solid tumor that will ultimately require surgery, such as a mast cell tumor, soft tissue/bone sarcoma, or an oral tumor, the following tests are typically recommended as part of the workup when indicated.

Diagnosing and Immunophenotyping Canine Lymphoma

Lymphoma is one of the most common cancers diagnosed in pet dogs, with the most frequent presenting clinical sign being “lumps” in the neck (ultimately determined to be peripheral lymphadenopathy on exam). Most primary care veterinarians are proficient at performing fine needle aspiration to confirm the diagnosis via cytology, either by shipping samples to a reference lab or digital cytology, which is available through multiple platforms. We encourage our primary care vets to also take the next step, which is to collect samples for immunophenotyping, i.e., B-cell vs. T-cell testing. The immunophenotype of lymphoma has a significant impact on prognosis (i.e., B-cell is better, T-cell is tougher) and in most progressive oncology practices, it will help the oncologist tailor the chemotherapy protocol. When the immunophenotyping information is available at the time of initial oncology consultation, it allows the specialist and pet owners to have a more informed and directed conversation about treatment options and expected prognosis. There are several options for immunophenotyping available, all of which can be performed by the primary care veterinarian via fine needle aspirate.

  1. Flow cytometry: This is almost always the test of choice for immunophenotyping because it can both confirm the diagnosis as well as provide prognostic information via subtyping, which allows for the differentiation of unique forms of lymphoma such as indolent T-zone lymphoma. Flow cytometry requires the cells to remain alive for analysis, so most labs either recommend placing the aspirate in a saline/serum solution in a non-additive tube or using a lab-provided tube pre-filled with cell media. Often this may necessitate having the owner bring the dog back to the clinic to perform this test, which can be done during the waiting period for referral. Typically, 2-3 aspirates will provide enough cells for analysis. A turbid solution usually indicates adequate cellularity for flow cytometry testing. Samples must be sent on cold packs (not ice) via overnight shipping to ensure cell survival.2
  2. Immunocytochemistry (ICC): ICC can be performed on cytology slides at some reference labs and does not require overnight shipping of cells in a fluid medium (as with flow cytometric analysis) or an incisional biopsy (as with IHC). The sample required for ICC submission is simply 4 adequately cellular, unstained or stained, air-dried glass slides prepared the same way as those for standard cytologic evaluation. While cell size and thus an impression of lymphoma grade/aggressiveness can be discerned through cytology with ICC, the determination is somewhat subjective and not as reliable as with flow cytometry.3
  3. PCR for antigen receptor rearrangement (PARR): PARR testing can be performed on both cytology and histopathology samples at most reference labs and universities. While choosing PARR saves the pet owner from having to bring the dog back for additional aspiration (as with flow cytometry), PARR will only provide a binary B-cell or T-cell designation and cannot differentiate the grade or subtype, so indolent forms may be missed. As such, PARR is most indicated when seeking to confirm lymphoma rather than to determine immunophenotype.

CADET® BRAF Mutation Detection Assay for Canine Transitional Cell Carcinoma/Urothelial Carcinoma (TCC/UC)

Transitional cell carcinoma (TCC), also known as urothelial carcinoma (UC), is the most common bladder cancer in dogs. Traditionally, diagnosis has required imaging, cytology, and often biopsy—each with limitations in sensitivity or risk of invasiveness.

Recent research has identified a specific mutation in the BRAF gene that occurs in about 85% of canine TCC/UC cases. This mutation, known as BRAF V595E (analogous to the human V600E mutation), was independently discovered by two research groups using different sequencing approaches—one comparing DNA from tumors versus normal tissues, and another analyzing RNA from affected tissue. The consistent discovery across both methods confirmed its strong association with TCC/UC.

Importantly, this BRAF mutation is not found in non-cancerous bladder tissues or in most other canine tumors, making it a reliable diagnostic biomarker.

The CADET® BRAF test (developed by Sentinel Biomedical; available through Antech Diagnostics)4 detects the presence of tumor cells carrying this mutation in free-catch urine samples. The assay is highly sensitive—able to identify as few as 10 cancer-bearing cells—and is not affected by blood or bacteria in the sample, unlike some older urine-based tests (e.g., VBTA). A second-generation assay has since been introduced to detect an additional 10% of cases that lack the original BRAF mutation, increasing overall detection sensitivity.

The CADET® BRAF test can detect TCC weeks to months before clinical signs such as hematuria, dysuria, or stranguria become apparent. Therefore, it is a valuable non-invasive diagnostic and screening tool for at-risk breeds (e.g., Scottish terriers, Shetland sheepdogs, West Highland white terriers) or dogs showing chronic lower urinary tract signs.

Nu.Q® Vet Cancer Test

Nucleosomes are small fragments of chromosomes that are released into the blood during cell death. It has been shown that high cellular turnover in diseases such as cancer can increase the level of nucleosomes in the bloodstream. The Nu.Q® Vet Cancer Test (developed by Volition; available through Antech Diagnostics and IDEXX) uses specific antibodies to quantify circulating nucleosomes (specifically H3.1 nucleosomes) in canine plasma to aid in cancer detection.

In a multicenter study of 528 dogs with confirmed malignancies versus 134 healthy controls, the assay demonstrated 97% overall specificity, with higher sensitivity for hematopoietic malignancies such as lymphoma (~77%), hemangiosarcoma (~82%), and histiocytic sarcoma (~62%). Sensitivity across all cancer types was approximately 49.8%, and for some localized solid tumors (e.g., mast cell tumors, osteosarcoma, soft tissue sarcoma) detection rates were low.

This test was designed to serve as a screening tool to be used as part of routine wellness checks. Significantly, nucleosome levels correlated with disease burden and response to therapy in hematopoietic cancers, suggesting there may also be some utility for monitoring remission and relapse. However, the test does not identify tumor location or type and should not be used as a replacement for imaging, cytology, or biopsy. Inflammation and other non-neoplastic causes can occasionally elevate nucleosome levels, though the high specificity of this test minimizes the chance of false positives in healthy dogs. Clinically, Nu.Q is best suited as an adjunctive screening and monitoring tool in older or high-risk dogs, or in conjunction with other diagnostics, rather than as a stand-alone test.5

Abbreviations:
CBC: cell blood count
ICC: immunocytochemistry
IHC: immunohistochemistry
TCC: transitional cell carcinoma (also called urothelial cell carcinoma)
UC: urothelial carcinoma (also called transitional cell carcinoma)
PARR: PCR for antigen receptor rearrangement
PCR: polymerase chain reaction
U/S: ultrasound

References:
1. https://www.carecredit.com/vetmed/costs/
2. https://vetmedbiosci.colostate.edu/chl/sample-collection-and-submission-instructions/
3. https://easternvetpath.com/our-services/#immunocytochemistry
4. https://www.antechdiagnostics.com/test/cadet-braf/
5. https://volition.com/nuq-vet-cancer-test-early-detection-dogs/

Resources:
• https://www.imprimedicine.com/flow-cytometry
• Mochizuki H, Shapiro SG, Breen M. Detection of BRAF mutation in canine cancers using PCR-based assay. PLos One. 2015;10(6):e0129534.
• Decker B, Parker HG, Dhawan D, et al. Homologous mutation to human BRAF V600E is common in naturally occurring canine bladder cancer—evidence for a relevant model system and a novel diagnostic test. Mol Cancer Res. 2015;13(6):993–1002.
• Mochizuki H, Kennedy K, Shapiro SG, et al. BRAF mutations in canine cancers and their value as diagnostic and prognostic biomarkers. Vet Pathol. 2017;54(6):846-853.
• Knapp DW, Dhawan D, Ostrander EA. New insights into canine bladder cancer and opportunities for comparative oncology. Nat Rev Urol. 2020;17(1):50-62.
• Wilson-Robles H, Pennell M, Rissetto K, et al. Evaluation of nucleosome concentrations in canine plasma for the detection of cancer. BMC Vet Res. 2022;18(1):323.
• De Remigio H, Ivey J, Wood J, et al. Plasma nucleosome concentrations for monitoring dogs with hematopoietic malignancies. Front Vet Sci. 2023;10:1184352.
• Volition Veterinary. Nu.Q® Vet Cancer Test: Detecting Cancer Early to Give Dogs and Their Owners a Brighter Tomorrow. White paper. Volition Veterinary. 2025. Accessed October 13, 2025.

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