Dr. Alonso received his DVM degree from the University of Brasilia, Brazil, in 2012, and in 2013 he moved to Belo Horizonte to do a 2-year-long internship program in veterinary clinical pathology at the Federal University of Minas Gerais Veterinary School, Brazil. There he also pursued and obtained his doctoral degree from the Department of Clinics and Surgery of the same institution, where him and his team developed a novel multiple regression model to classify canine cavitary effusions using biochemical parameters. Between 2015 and 16 he worked as a consulting clinical pathologist for private labs and in 2021 he completed a residency in veterinary clinical pathology at the UC Davis veterinary medical teaching hospital, USA, being awarded with the best research study in small animals when investigating the lipoprotein profile of canine and feline cavitary transudates. In 2022 he became board certified in clinical pathology by the American College of Veterinary Pathology and, between the years of 2021 and 2022, he served as an assistant professor of clinical pathology at the Ross University School of Veterinary Medicine, in the West Indies, for 4 semesters. There he had a research grant proposal approved to study the epidemiologic and hematologic aspects of Dirofilaria spp. infection in cats in the Caribbean. In 2023, he joined the Department of Comparative Medicine as a clinical assistant professor and director of the animal diagnostic laboratory.

Academic Appointments

Administrative Appointments

  • Director, Animal Diagnostic Laboratory, Stanford University, School of Medicine, Department of Comparative Medicine (2023 - Present)

Honors & Awards

  • Gerald V. Ling Award - Outstanding Small Animal Research Study and Presentation, University of California, Davis, Veterinary Medical Teaching Hospital (2021)

Boards, Advisory Committees, Professional Organizations

  • Diplomate, American College of Veterinary Pathologists (2022 - Present)

Professional Education

  • Resident, University of California, Davis, School of Veterinary Medicine, Veterinary Medical Teaching Hospital, Clinical Pathology (2021)
  • PhD, Universidade Federal de Minas Gerais, Laboratory Medicine and Pathology (2019)
  • DVM, Universidade de Brasília (2012)

All Publications

  • Can nematode infection cause internal bleeding in dogs? A case of Dirofilaria immitis infection in cavitary fluids. Veterinary clinical pathology Alonso, F. H., Shapiro, K., Camp, L. E. 2024


    A 9-year-old dog was presented with weight loss, respiratory effort, and an enlarged abdomen. Imaging studies and exploratory surgery showed pulmonary and splenic masses and bi-cavitary effusion, later classified as hemorrhage. Cytology of the peritoneal and pleural fluids also revealed several microfilariae. Immunologic and molecular analyses confirmed Dirofilaria immitis infection and histopathology of the spleen indicated a cavernous endothelial proliferation with undefined etiology (hemangiosarcoma vs reaction to parasite infestation). The nematode larvae are speculated to have entered body cavities via erratic migration or via hemorrhage and visceral lesions to be related to parasitism. Nematode infection should be considered as a differential diagnosis for internal bleeding of undetermined origin.

    View details for DOI 10.1111/vcp.13351

    View details for PubMedID 38684482

  • Dyspnea, nonproductive cough, and inappetence in an 8-year-old mixed-breed dog. Journal of the American Veterinary Medical Association Feng, J., de Rosayro, R., Peda, A., Alonso, F. H., Bolfa, P. 2023: 1-4

    View details for DOI 10.2460/javma.23.05.0284

    View details for PubMedID 37532239

  • Agglutination and hemolytic crossmatching to determine transfusion reaction differences between large and small breed goats JOURNAL OF VETERINARY INTERNAL MEDICINE Kretsch, C. M., Alonso, F. H., Buktenica, M., Heller, M. C. 2023


    Blood transfusions are performed frequently in goats, but crossmatches are rarely performed.Determine differences in the frequency of agglutination and hemolytic crossmatch reactions between large and small breed goats.Healthy adult goats, 10 large and 10 small breed.Two hundred eighty major and minor agglutination and hemolytic crossmatches: 90 large breed donor to large breed recipient (L-L), 90 small breed donor to small breed recipient (S-S), 100 large breed donor to small breed recipient (L-S). A linear mixed model with treatment group (L-L, S-S, L-S) as a fixed effect and individual crossmatch as a random effect was used to identify variations in reaction frequency among groups and individuals.Frequency of major agglutination reactions for L-L, S-S, and L-S were 3/90 (3.3%), 7/90 (7.8%), and 10/100 (10.0%), respectively. Frequency of major hemolytic reactions for L-L, S-S, and L-S were 27/84 (32.1%), 7/72 (9.7%), and 31/71 (43.7%). Individual pairings and groupings had no effect on agglutination reactions. Individual pairings had no effect on the frequency of hemolytic reactions. For major hemolytic crossmatches, pairwise comparisons identified higher frequencies of reactions when comparing L-L to S-S (P = .007) and L-S to S-S (P < .001).Goats experience increased frequencies of hemolytic reactions compared to agglutination. Significant increases in hemolysis were seen between large breed donors and small breed recipients, compared to small breed pairings. Additional studies are required to determine correlations between crossmatches and transfusion reactions.

    View details for DOI 10.1111/jvim.16738

    View details for Web of Science ID 000992786400001

    View details for PubMedID 37226646

  • Validation and method comparison for a point-of-care lateral flow assay measuring equine whole blood insulin concentrations JOURNAL OF VETERINARY DIAGNOSTIC INVESTIGATION Berryhill, E. H., Urbina, N. S., Marton, S., Vernau, W., Alonso, F. H. 2023; 35 (2): 124-131


    The Wellness Ready Test (WRT) is a lateral flow, stall-side assay that measures equine insulin in whole blood and requires validation before recommending clinical use. We evaluated intra- and inter-assay precision and linearity and compared the WRT with a radioimmunoassay (RIA). Tested concentrations ranged from <139 to >695 pmol/L (<20 to >100 μIU/mL). For 20 replicates at each insulin level, intra-assay CVs of the WRT for insulin were 13.3%, 12.9%, and 15.3% at low (139-278 pmol/L; 20-40 μIU/mL), intermediate (278-417 pmol/L; 40-60 μIU/mL), and high (>417 pmol/L; >60 μIU/mL) concentrations, respectively. For 10 replicates at each level (3 assay lots), inter-assay CVs were 15.9%, 11.0%, and 11.7%, respectively. In the weighted linear regression of 5 measured insulin concentrations against expected concentrations, R2 = 0.98, slope = 1.02, and y-intercept = 14.4 pmol/L (2.08 μIU/mL). The Spearman correlation coefficient (rs) was 0.90 (95% CI: 0.85-0.94) between the WRT and RIA; the WRT = f(RIA) Passing-Bablok regression yielded the fit, y = 1.005x + 24.3 pmol/L (3.50 μIU/mL). The WRT result averaged 10.4% higher than the RIA result, with targeted bias of 25.9, 26.1, and 26.7 pmol/L (3.74, 3.76, and 3.84 μIU/mL) for cutoffs used to diagnose insulin dysregulation of 312, 347, and 451 pmol/L (45, 50, and 65 μIU/mL). Assay clinical sensitivities, specificities, and accuracies determined at the 3 selected clinical cutoffs and using the RIA as gold standard were 87-95%, 92-96%, and 91-95%, respectively (n = 99 samples). Observed total error was 28.4-30.4%. The WRT had acceptable precision, excellent linearity, and good association with the RIA.

    View details for DOI 10.1177/10406387221142288

    View details for Web of Science ID 000895952800001

    View details for PubMedID 36482705

    View details for PubMedCentralID PMC9999392

  • Exertional hemolysis and hematuria in a Labrador Retriever dog JOURNAL OF VETERINARY DIAGNOSTIC INVESTIGATION Saint-Pierre, L. M., Burkitt-Creedon, J. M., H. Alonso, F., Wun, M. K. 2022; 34 (6): 968-971


    A 7-y-old male Labrador Retriever dog was presented because of acute onset of dark-colored urine after a hunting session the day prior. Moderate hemoglobinemia was observed, associated with transient hemoglobinuria and hematuria with no concurrent evidence of underlying urinary tract disease. The patient's clinical signs resolved within 36 h post-exercise without specific treatment. The concurrent occurrence of exertional hemolysis and hematuria in a dog is uncommon; these conditions are commonly reported separately in human athletes.

    View details for DOI 10.1177/10406387221127268

    View details for Web of Science ID 000862617900001

    View details for PubMedID 36184929

    View details for PubMedCentralID PMC9597330

  • Case Report: Cytologic Description of Somatotroph Pituitary Adenoma in a Cat FRONTIERS IN VETERINARY SCIENCE Alonso, F. H., Niedringhaus, K. D., Ceregatti, M. G., Maglaty, M. A. 2022; 9: 934009


    This case report describes for the first time the cytologic characteristics of a hormonally secreting pituitary adenoma in a cat. An 8-year-old female spayed domestic long-haired cat was referred with a previous diagnosis of hypersomatotropism and secondary diabetes mellitus 7 months prior. Clinical signs included weight loss, polyphagia, polyuria, and polydipsia. Serum insulin-like growth factor-1 was 340 nmol/L (RI: 12-92), and CT scan revealed a hypophyseal mass, and a presumptive diagnosis of acromegaly was made. A transsphenoidal hypophysectomy was performed. A fragment of the pituitary gland was subjected to a squash preparation and cytology revealed a neuroendocrine neoplasm characterized by anisokaryosis and prominent nucleoli. Additional cytologic findings included cell cohesiveness, indistinct cytoplasmic borders, nuclear crowding, molding, and fragmentation. A diagnosis of adenoma was based on a lack of histopathologic or imaging evidence of invasion. A week later, during post-surgical hospitalization, the patient worsened and died. Histopathology from a necropsy procedure revealed fibrinosuppurative meningitis as a post-surgical complication. Pituitary adenomas might have an aggressive cytologic appearance, despite a lack of histopathologic invasion or dissemination.

    View details for DOI 10.3389/fvets.2022.934009

    View details for Web of Science ID 000834560200001

    View details for PubMedID 35923821

    View details for PubMedCentralID PMC9339988

  • Laboratory diagnosis of canine uroperitoneum based on cellular and biochemical characteristics of serum and abdominal fluid VETERINARY CLINICAL PATHOLOGY Paes, P. O., Alonso, F. H., Chaves, N. G., Andrade, A. M., Ceregatti, M. G., Horta, R. S. 2022; 51 (1): 107-111


    Literature on the laboratory diagnosis of uroperitoneum is scarce, and it is mostly based on the biochemical findings of cavitary fluid and serum. Cell count and protein concentrations measurements are rarely used and available studies on this subject are based on a relatively small cohort of individuals.We aimed to use a large sample pool of dogs to establish cutoff points for biochemical analytes in cavitary fluids and serum for the diagnosis of uroperitoneum. We also sought to evaluate the general classification of these cavitary fluids.In a retrospective and prospective study, 180 canine abdominal effusion cases were evaluated, 30 of which were uroperitoneum (uroperitoneum group, UG) and 150 with other etiologies (non-uroperitoneum group, NUG).The results showed that 83.3% of UG and 12.7% of NUG abdominal fluid cases were not classified as transudates or exudates. The use of specific cutoffs for fluid creatinine concentrations (≥2.1 mg/dL) and fluid:serum creatinine ratios (Cf: Cs ≥ 1.25) in these unclassified effusions resulted in an accuracy of 99.0% for the laboratory diagnosis of uroperitoneum.The adoption of a new set of criteria and cutoffs based on the combination of parameters such as TP, TNCC, fluid creatinine and Cf: Cs improves the diagnosis of uroperitoneum in dogs.

    View details for DOI 10.1111/vcp.13046

    View details for Web of Science ID 000761817700001

    View details for PubMedID 35181924

  • Lipoprotein profile of pleural and peritoneal transudates in dogs and cats JOURNAL OF VETERINARY INTERNAL MEDICINE Alonso, F. H., Behling-Kelly, E., Borjesson, D. L. 2022; 36 (2): 464-472


    Current diagnostic evaluation of transudative effusions rarely aids in identifying an underlying etiology. Lipoproteins in the fluid might reflect the site or nature of vessel involvement.Improve the classification and diagnostic utility of pleural and peritoneal transudates in dogs and cats by investigating lipoprotein patterns in effusions. Compare these patterns with other peritonaeal and pleural fluid variables and underlying diseases.Samples of transudates and serum from 18 cats and 37 dogs with transudative effusion (total nucleated cell count [TNCC] <5000 cells/μL) were analyzed.Lipoprotein fractions, triglyceride, and cholesterol (CHO) concentrations were prospectively determined in paired fluid and serum samples. Standard fluid measurements were retrospectively collected.Two distinct fluid lipoprotein patterns were noted. Fluids rich in VLDL+IDL were associated with chronic kidney disease, acquired portosystemic shunts or protein-losing enteropathy (group I). Fluids rich in denser lipoproteins were associated with underlying heart disease, caudal vena cava syndrome or intracavitary neoplasia (group II). Group I and group II also had significant differences between fluid concentrations of CHO (x̄ = 8 vs 110 mg/dL) and TP (x̄ = 0.6 vs 3.8 g/dL), respectively. Five peritoneal transudates were triglyceride-rich (>100 mg/dL) and associated with pancreatitis.Protein-poor (TP <1.5 g/dL) and protein-rich (TP >2.5 g/dL) transudates were associated with distinct lipoprotein patterns and specific groups of disease. Effusions secondary to pancreatitis might be transudative and rich in triglycerides.

    View details for DOI 10.1111/jvim.16369

    View details for Web of Science ID 000755023600001

    View details for PubMedID 35166405

    View details for PubMedCentralID PMC8965250

  • Glucose and Lactate Reference Intervals for White Sturgeon and Evaluation of Two Point-of-Care Devices in Sturgeon Infected with Veronaea botryosa JOURNAL OF AQUATIC ANIMAL HEALTH Hagen, K. B., Lima, K., Ang, J., Montealegre-Golcher, F., Alonso, F. H., Soto, E. 2022; 34 (1): 28-37


    White Sturgeon Acipenser transmontanus are cultured for human consumption as well as for conservation purposes. In this study, two commercially available portable devices for measuring glucose and lactate were compared to a benchtop analyzer and blood reference intervals were generated using heparin plasma collected from 43 healthy White Sturgeon yearlings. The generated normal ranges were used to compare plasma values collected from Veronaea botryosa-infected White Sturgeon at 10, 20, and 30 d postchallenge (dpc). In the 43 healthy yearlings, significantly different glucose and lactate values were obtained when comparing the portable devices to the benchtop analyzer. In the portable devices, blood glucose showed a consistent bias of 12.3 mg/dL and blood lactate showed a proportional bias. The detected blood glucose values in infected sturgeon were significantly different from those in noninfected controls when using the benchtop analyzer at 20 and 30 dpc and when using the portable device at 20 dpc. However, blood glucose in infected individuals and controls was within the reference interval on either device. No significant difference was noted for lactate measurements in infected sturgeon. The results of this study indicate that portable devices for blood glucose and blood lactate evaluation in White Sturgeon may be useful in a setting where relative values are an acceptable approximation of absolute values.

    View details for DOI 10.1002/aah.10146

    View details for Web of Science ID 000740985400001

    View details for PubMedID 35014103

  • Atypical cytomorphologic description of a seminoma in a rabbit VETERINARY MEDICINE AND SCIENCE Alonso, F. H. 2022; 8 (1): 121-124


    Seminoma is reported as a rare disease associated with specific micro-morphologic findings. In the present report, we describe the case of a testicular seminoma in a 7-year-old Holland Lop rabbit, in which the cytology presented an atypical pattern. Upon presentation, the left testicle was severely enlarged, and the patient also had a history of radiation therapy for a previously diagnosed thymoma. Following excision and histopathology of the abnormal organ, results showed a mixed intratubular-diffuse pattern with evidence of torsion. Moreover, cytology revealed a cohesive pattern with multiple malignancy criteria. To our knowledge, this is the first published report of a seminoma with these cytologic features.

    View details for DOI 10.1002/vms3.682

    View details for Web of Science ID 000728584600001

    View details for PubMedID 34889525

    View details for PubMedCentralID PMC8788883

  • Pathology in Practice JAVMA-JOURNAL OF THE AMERICAN VETERINARY MEDICAL ASSOCIATION Alonso, F. H., Choi, E., Borchers, A., Darling, S. L., Vasilatis, D., Kol, A. 2021; 259: 1-4


    In collaboration with the American College of Veterinary Pathologists.

    View details for DOI 10.2460/javma.19.06.0296

    View details for Web of Science ID 000731761700002

    View details for PubMedID 34910673

  • The predominance and diagnostic value of neutrophils in differentiating transudates and exudates in dogs VETERINARY CLINICAL PATHOLOGY Alonso, F. H., Christopher, M. M., Paes, P. O. 2021; 50 (3): 384-393


    There is disagreement in the literature about the proportion of neutrophils expected in canine transudates. A cutoff of <30% neutrophils has been recommended for distinguishing transudates from exudates, but its validity has not been established.The aim of this study was to evaluate differential cell counts in canine effusions and analyze the percentage and number of neutrophils in transudates and exudates.Effusion data were obtained retrospectively from 263 dogs with pleural or peritoneal effusion. Low-protein transudates, high-protein transudates, and exudates were classified using the total protein (TP) concentration and total nucleated cell count (TNCC). Differential percentages and absolute neutrophil counts were compared by the effusion type and underlying etiology.Low-protein transudates (n = 63), high-protein transudates (n = 84), and exudates (n = 77) had a median (range) of 35% (0%-100%), 59% (0%-100%), and 90% (50%-98%) neutrophils (P < .0001). All effusions with <50% neutrophils were transudates, but 53% of transudates had ≥50% neutrophils, and 69% had ≥30%. Median neutrophil counts were 62/µL (0-892/µL), 538/µL (0-4550/µL), and 45 590/µL (5400-496 800/µL) in low-protein transudates, high-protein transudates, and exudates, respectively (P < .0001). Neutrophil counts correlated with TNCC (r2  = 0.99), such that using neutrophil cutoffs did not affect effusion classifications in most cases. Neutrophil percentages and counts were higher in effusions from dogs with uroabdomen and sepsis (P < .01); neutrophil counts were lower in dogs with hepatic insufficiency (P < .0001). Uroabdomen usually caused low-protein, high-neutrophil exudates.Although effusions with <50% neutrophils are transudates, most transudates and exudates have ≥50% neutrophils, limiting the diagnostic usefulness of % neutrophils for classifying effusions. Absolute neutrophil cutoffs did not notably improve effusion classification but could warrant future studies.

    View details for DOI 10.1111/vcp.12987

    View details for Web of Science ID 000701454900012

    View details for PubMedID 34337780

  • Evaluation of a new multiple regression model based on biochemical parameters for the distinction of canine exudates and transudates VETERINARY CLINICAL PATHOLOGY Alonso, F. H., Mattoso, C. S., Leme, F. P., Paes, P. O. 2021; 50 (3): 394-403


    The classification of effusions in human medicine currently uses biochemical parameters of verified analytical accuracy, while veterinary medicine is traditionally guided by protein content (TP) and total nucleated cell count (TNCC) in the effusion, without solid scientific support.We aimed to assess the accuracy of the current veterinary classification system to distinguish transudates from exudates and create new tools involving biochemical parameters that better classify canine cavitary effusions.Clinical, laboratory, and imaging data from 250 canine pleural and peritoneal effusions were retrospectively and prospectively collected, organized, and statistically evaluated. Multiple logistic regression analysis was performed using biochemical and cellular parameters.For identifying exudates, the accuracy (87.7%, n = 204) of the best traditional classification system (TNCC > 3000 cells/μL) was similar to that of the individual biochemical cutoff values with the greatest accuracy in the abdominal cavity (eg, cholesterol, CHO-E > 40.1 mg/dL, 87.3%, n = 55). The accuracy of albumin (ALB-E > 0.8 g/dL) in the pleural cavity was nonetheless higher (100%, n = 23). The best multiple predictive models for any cavity used the percentage of neutrophils and CHO-E (n = 72), presenting an accuracy, sensitivity, and specificity for the diagnosis of exudate of 88%, 96%, and 67%, respectively.Biochemical classification of pleural effusions has a higher accuracy than the traditional system (based on TP and TNCC). Utility and cutoff of analytes are different for each cavity. Implementing a multiple regression model or establishing ratios or gradients with concurrent serum values adds no significant improvement in the diagnostic potential of distinguishing transudate and exudates in dogs.

    View details for DOI 10.1111/vcp.12945

    View details for Web of Science ID 000687869900001

    View details for PubMedID 34431116

  • Gelatinous transformation of bone marrow in a rabbit JOURNAL OF VETERINARY DIAGNOSTIC INVESTIGATION Alonso, F. H., Tarbert, D. K., Wu, B., Rodriguez, P., Christopher, M. M. 2021; 33 (6): 1183-1187


    A 9-y-old, spayed female rabbit was presented for evaluation of hypoglycemia and lateral recumbency. The patient was hypothermic and had diffuse muscle wasting; weight loss since a previous visit was also noted. Hematologic abnormalities included progressive nonregenerative anemia and severe heteropenia. Evaluation of a bone marrow aspirate sample revealed active hematopoiesis with abundant pink matrix. The matrix material stained positively with periodic acid-Schiff and alcian blue, and a diagnosis of gelatinous transformation of the bone marrow (GTBM, serous atrophy of fat) was made. Although its precise prevalence remains to be determined, GTBM should be suspected in rabbits with persistent cytopenias following prolonged starvation or gastrointestinal disease.

    View details for DOI 10.1177/10406387211029916

    View details for Web of Science ID 000675161300001

    View details for PubMedID 34250866

    View details for PubMedCentralID PMC8546475

  • Mandibular metastasis of a prostatic carcinoma in a dog VETERINARY MEDICINE AND SCIENCE Michalak, S. R., Woerde, D. J., Wilson, S. S., Alonso, F. H., Hardy, B. T. 2021; 7 (5): 1488-1492


    Skeletal metastasis is a common finding in dogs with prostatic carcinoma and most frequently involves the lumbar vertebrae and pelvis. In the present report, we describe the case of a prostatic carcinoma in a 6-year-old Labrador retriever, who developed apparent oral sensitivity and pain within a week of initial diagnosis. Computed tomography of the skull revealed a mixed osteoproductive and osteolytic mass of the condylar process of the left mandible, and cytologic evaluation of the mass was consistent with metastatic prostatic carcinoma. To our knowledge, this is the first published report of mandibular metastasis of a prostatic carcinoma in a dog.

    View details for DOI 10.1002/vms3.513

    View details for Web of Science ID 000647430000001

    View details for PubMedID 33955707

    View details for PubMedCentralID PMC8464293

  • Canine leishmaniasis in Northern California-A case report VETERINARY CLINICAL PATHOLOGY Alonso, F. H., Vasilatis, D. M., Veluvolu, S. M., Willcox, J. L., Scorza, B. M., Petersen, C. A., Kol, A. 2021; 50 (1): 71-75


    A 3-year-old dog was referred to the Veterinary Medical Teaching Hospital of the University of California-Davis for further evaluation of episodes of epistaxis of 1-year duration and peripheral lymphadenopathy. The patient had a history of atopic dermatitis with no travel history outside of California. Hyperglobulinemia with a polyclonal gammopathy was noted on serum protein electrophoresis. Microscopic evaluation of a bone marrow aspirate sample revealed many free and intra-cellular amastigotes of Leishmania sp. that was further confirmed by qPCR as L infantum. This is, to the best of our knowledge, the first reported case of canine leishmaniasis in the state of California. The patient is believed to have been vertically infected from the dam who is from Serbia and remained subclinical until presentation. Because the clinical progression of leishmaniasis is variable, it is important that precautions be discussed with owners acquiring puppies with dams from endemic regions of leishmaniasis to prevent zoonotic exposure in states where competent vectors are present.

    View details for DOI 10.1111/vcp.12956

    View details for Web of Science ID 000630816300001

    View details for PubMedID 33745143

  • What is your diagnosis? Peritoneal effusion in a 7-year-old dog VETERINARY CLINICAL PATHOLOGY Alonso, F. H., Roy, M. A., Kol, A. 2020; 49 (4): 678-680

    View details for DOI 10.1111/vcp.12905

    View details for Web of Science ID 000599619300001

    View details for PubMedID 33336818

  • Prognostic values of physical and hematological parameters of dogs naturally infected with parvovirus PVC-2: retrospective study of 103 cases ARQUIVO BRASILEIRO DE MEDICINA VETERINARIA E ZOOTECNIA Alves, F. S., Alonso, F. H., Horta, R. S., Barbosa, B. C., Beier, S., Paes, P. O. 2020; 72 (6): 2127-2134
  • Canine cavitary effusion: a retrospective study of 304 cases in Brazil ARQUIVO BRASILEIRO DE MEDICINA VETERINARIA E ZOOTECNIA Alonso, F. H., Bulla, C., Paes, P. O. 2019; 71 (3): 869-877