Romiplostim for treatment of thrombocytopenia in dogs: A retrospective assessment and clinical outcomes.

BACKGROUND: Romiplostim, a thrombopoietin analog, is commonly used to treat immune-mediated thrombocytopenia (ITP) in humans, but its use in dogs remains limited. OBJECTIVES: Evaluate the effects and adverse events of romiplostim administration in dogs with thrombocytopenia caused by various underlying diseases. ANIMALS: Forty-two client-owned dogs with naturally occurring thrombocytopenia at 2 referral animal hospitals. METHODS: Retrospective, multi-institutional analysis to evaluate the outcomes of romiplostim treatment in dogs. RESULTS: Among the dogs treated with romiplostim, 27 experienced an increase in platelet count and 26 maintained a platelet count within the reference range. Platelet count improvement was observed in various conditions: primary ITP (90%, n = 18/20), pancytopenia of unknown etiology (42.9%, n = 3/7), chemotherapy-induced thrombocytopenia (50%, n = 3/6), babesiosis (100%, n = 1/1), radiotherapy-induced thrombocytopenia (0%, n = 0/1), and disseminated intravascular coagulopathy (33.3%, n = 2/6). The median time for platelet recovery (>50 000/µL) after romiplostim administration was 4 days, and the median time for platelet count normalization was 7 days. Median hospitalization time for the improvement group (I) was 5 days. The survival-to-discharge rates were 85%, 40%, and 28.6% for dogs with primary ITP, secondary thrombocytopenia, and thrombocytopenia of unknown etiology, respectively. CONCLUSIONS AND CLINICAL IMPORTANCE: Romiplostim is a well-tolerated and promising treatment for primary ITP in dogs, suggesting its potential as a valuable therapeutic option for dogs with thrombocytopenia caused by various underlying conditions. These findings emphasize the need for further research to optimize romiplostim dosing and understand its role in treating secondary thrombocytopenia and pancytopenia of unknown etiology.

Can neutrophil-to-lymphocyte and platelet-to-lymphocyte ratios be used as markers for hypercortisolism in dogs?

Changes in neutrophil-to-lymphocite ratio (NLR) and platelet-to-lymphocyte ratio (PLR) have been identified in dogs with hypercortisolism (HC), but, no studies have investigated the changes in these inflammatory biomarkers as cost-effective and available parameters for the diagnosis and management of HC. This study was performed to evaluate whether NLR and PLR could be used as biomarkers for the diagnosis and treatment response in dogs with HC. This retrospective study included 67 dogs with HC, 58 dogs with non-adrenal illness (NAI), and 39 healthy dogs. NLR and PLR were compared among the three groups. Cut-off values of NLR and PLR for HC screening and percent change in biomarkers for assessing treatment response were evaluated. In addition, the NLR and PLR were compared before and after trilostane treatment. NLR and PLR were significantly higher in the HC group than in the NAI and healthy groups. The NLR cut-off value of 4.227 had a sensitivity of 67.16% and specificity of 65.52%, and the PLR cut-off value of 285.0 had a sensitivity of 56.72% and specificity of 70.69% for differentiating between dogs with HC and those with NAI, respectively. Furthermore, a significant decline in NLR was observed after treatment in the well-controlled HC group. The cutoff value of percent change in NLR to identify well-controlled HC was -7.570%; sensitivity and specificity were 100% and 63.64%, respectively. Therefore, NLR and PLR might be used cautiously as supportive biomarkers for HC diagnosis, and NLR could be a potential monitoring tool in assessing the treatment response of HC in dogs.

Evaluation of darbepoetin therapy on platelet count and function in healthy cats and cats with surgically induced chronic kidney disease.

OBJECTIVE: To evaluate the effects of darbepoetin on platelet population and reactivity in healthy cats (HCs) and azotemic cats with remnant kidney (RK) model-induced chronic kidney disease. ANIMALS: 12 purpose-bred domestic shorthair cats (n = 6 HCs and n = 6 RK). METHODS: In this pilot study, all cats received darbepoetin (1 µg/kg, SC) on days 0, 7, and 14. Blood was sampled at baseline and on days 3, 10, 15, 17, 20, and 21. At each time point, a CBC was performed, platelet aggregometry was assessed by impedance and optical methods, and platelet P-selectin (CD62P) was quantified before and after thrombin stimulation. Additionally, reticulated platelets were quantified using both thiazole orange staining and proprietary analysis by the CBC analyzer. For RK cats, systemic blood pressure (BP) was serially measured. RESULTS: No adverse effects of darbepoetin were seen. There was no statistically significant change in platelet count between or within groups at any time point. Hematocrit increased significantly over time in the RK but not the HC group. RBC reticulocyte numbers in both groups increased over time. Reticulated platelet percentage did not increase in either group. Differences in platelet reactivity within or between groups were not seen in the aggregometry or flow cytometric assessments. In RK cats, indirect BP did not significantly change during the study. CLINICAL RELEVANCE: This preliminary investigation did not find evidence that darbepoetin administration impacted platelet number, reactivity, nor reticulated platelet count. Anemic RK cats experienced increased hematocrit and RBC reticulocytes as expected with darbepoetin therapy.

Prothrombin and activated partial thromboplastin times, thromboelastography, hematocrit, and platelet count in a feline hemorrhage/over-resuscitation model using lactated Ringer's solution or 6% tetrastarch 130/0.4.

OBJECTIVE: To describe and compare prothrombin time (PT), activated partial thromboplastin time (aPTT), thromboelastography (TEG), HCT, and platelet count measurements in a hemorrhage/over-resuscitation model. DESIGN: Randomized crossover study. SETTING: University teaching hospital. ANIMALS: Six cats. INTERVENTIONS: Anesthetized cats underwent 3 treatments at 2-month intervals. The treatments were as follows: NHR-no controlled hemorrhage and sham resuscitation; LRS-controlled hemorrhage and lactated Ringer's solution (LRS) for resuscitation; and Voluven-controlled hemorrhage and 6% tetrastarch 130/0.4 for resuscitation. The LRS and Voluven were administered at 60 and 20 mL/kg/h, respectively, for 120 minutes. Blood samples were drawn for PT, aPTT, TEG, HCT, and platelet count measurements at a healthy check (T - 7d), after controlled hemorrhage (T0), at 60 and 120 minutes of resuscitation (T60 and T120), and at 24 hours after completion of resuscitation (T24h). Data were analyzed using a general linear mixed model approach (significance was P < 0.05). MEASUREMENTS AND MAIN RESULTS: Total median blood loss (controlled hemorrhage and blood sampling from T0 to T120) at T120 was 11.4, 31.0, and 30.8 mL/kg for NHR, LRS, and Voluven, respectively. PT and aPTT during LRS and Voluven were prolonged at T60 and T120 compared to NHR (P < 0.001). On TEG, the reaction time, kinetic time, and alpha-angle were within reference intervals for cats at all time points in all treatments, while maximum amplitude was less than the reference interval (40 mm) at T0, T60, and T120 during Voluven and at T60 and T120 during LRS compared to NHR (both P < 0.001). The HCT and platelet count were significantly lower at T60 and T120 during LRS and Voluven compared to NHR (P < 0.001). CONCLUSIONS: Hypocoagulopathy was observed during hemorrhage and liberal fluid resuscitation. Prolongation of PT and aPPT and decreased clot strength may have been caused by hemodilution and platelet loss.

Kanamycin treated-ethylenediamine tetraacetic acid-dependent pseudothrombocytopenia in blood specimen of cats.

Background: Pseudothrombocytopenia is a commonly obtained false negative result when analyzing feline platelet (PLT) count by an automated machine. It is related to ethylenediamine tetra-acetic acid (EDTA), a widely utilized anticoagulant in blood collection tubes, resulting in EDTA-dependent pseudothrombocytopenia (EDTA-PTCP). Aim: To investigate whether treated with kanamycin enhanced the quantity of PLT aggregations in feline blood specimens collected using EDTA-PTCP. Methods: Thirty-one blood samples were obtained using EDTA tubes. The complete blood count was analyzed using an automated Mindray BC-5000Vet. Both Manual cell counts and thin blood smears were performed to estimate the amount of red blood cell, white blood cell, and PLTs as well as to evaluate the severity scores of PLT clumping, respectively. Comparisons were made between those pre-treated and those treated with kanamycin in the EDTA tube. Results: There were significantly different mean PLT counts in the samples before and after they were treated with kanamycin, both on automated (156.6 ± 76.4 vs. 260.3 ± 115.5; p < 0.001) and manual (168.5 ± 92.1 vs. 262.8 ± 119.6; p < 0.001) readings, with a 95% confidence interval of 0.19 (0.022-0.365). Conclusion: This study suggests that in clinical laboratory practice, kanamycin should be added to feline blood specimens with EDTA-PTCP.

Evaluation of clopidogrel, hypercoagulability, and platelet count in dogs undergoing splenectomy for splenic masses.

Dogs that had splenectomy are predisposed to fatal thrombotic conditions, and thrombocytosis is a risk factor for post-splenectomy hypercoagulability. However, in veterinary medicine, there are no specific therapeutic approaches for managing this hypercoagulability. This study aimed to determine the preventive effect of clopidogrel on post-operative hypercoagulability during the first 2 weeks post-splenectomy in dogs with splenic masses. This study included 12 dogs that had splenectomy. Seven dogs received no treatment (group A), and five were treated with clopidogrel (group B). Clopidogrel was loaded at 10 mg/kg on day 2 and continued at 2 mg/kg until day 14. Blood samples were collected on the day of surgery and 2, 7, and 14 days after splenectomy in both groups. In group B, thromboelastography (TEG) was performed on the same days. In group A, there was significant elevation of platelet counts on days 7 (p = 0.007) and 14 (p = 0.001) compared to day 0. In group B, the platelet counts were significantly elevated on day 7 (p = 0.032) but no significant difference was found on day 14 compared to day 0. Platelet counts on day 14 were significantly higher in group A than in group B (p = 0.03). The lower platelet counts were correlated with alterations in TEG parameters, and no significant differences were found in the K and α-angle values at all postoperative assessment points compared to day 0. Our study suggests that clopidogrel may reduce post-operative thrombocytosis and hypercoagulability in dogs that undergo splenectomy for splenic masses.

Utility of immature platelet fraction in the Sysmex XN-1000V for the differential diagnosis of central and peripheral thrombocytopenia in dogs and cats.

BACKGROUND: The immature platelet fraction (IPF), a parameter obtained by the Sysmex XN-1000V analyzer, is used in humans to differentiate between central (CEN) and peripheral (PER) thrombocytopenia (TP) but has not been evaluated in small animals. OBJECTIVES: Compare IPF between healthy, clinical non-TP and TP dogs and cats, study IPF in different causes of TP in dogs and cats and, establish IPF reference intervals (RIs), and study the effect of age and sex on IPF in healthy dogs and cats. ANIMALS: A total of 3281 dogs and 726 cats. METHODS: Retrospective review of medical records. Animals were classified as nonthrombocytopenic (healthy group and group of clinical patients without TP [NTP]) or TP. These latter animals were subclassified as pseudothrombocytopenia (PSE), CEN and PER, based on evaluation of platelet clumps, estimated platelet count in blood smears and final diagnosis. Blood samples were evaluated using a Sysmex XN-1000V with a specific platelet channel (PLT-F). RESULTS: The IPF was significantly different between each subtype of TP in both species. Immature platelet fractions <6.9% in dogs or 13.6% in cats, once PSE has been eliminated by review of blood smears, are indicative of CEN. Reference intervals for IPF were 0.5%-8% in healthy dogs and 1%-40.3% in healthy cats. CONCLUSIONS AND CLINICAL IMPORTANCE: We determined that IPF can differentiate between CEN and PER in dogs and cats, guiding additional testing and avoiding more invasive procedures (bone marrow sampling). A blood smear always should be evaluated to rule out platelet clumping.

Effects of canine influenza infection and DA2PP vaccination on the development of platelet-associated immunoglobulins and platelet counts in dogs.

BACKGROUND: Immune thrombocytopenia (ITP) is commonly associated with platelet-associated immunoglobulins (PAIg). Demonstration of PAIg can help determine etiologies for thrombocytopenia. In humans, ITP and thrombocytopenia have been associated with various vaccinations and influenza infections, respectively. OBJECTIVES: We aimed to evaluate platelet counts and PAIg in research dogs with H3N2 and in research and client-owned dogs routinely vaccinated for distemper, adenovirus-2, parainfluenza, and parvovirus (DA2PP). The hypotheses were that H3N2 infection but not DA2PP vaccination would decrease platelet counts, and neither would result in the detection of PAIg. METHODS: Three pilot studies. Platelet counts and PAIg, measured by direct flow cytometry as %IgG, were evaluated in eight research Beagles following experimental infection with H3N2 (experiment 1), nine research Beagles vaccinated for DA2PP (experiment 2), and thirty client-owned dogs vaccinated for DA2PP (experiment 3). All animals were considered healthy at the start of the experiments. RESULTS: Transient, self-resolving decreases in platelet counts and increases in %IgG occurred following H3N2 infection, and one dog became thrombocytopenic and positive for PAIg. Following DA2PP vaccination, %IgG increased in research and client-owned dogs, but only one dog was considered positive for PAIg with a concurrent increase in platelet count. Mean PAIg increased from baseline in client-owned dogs following vaccination. CONCLUSIONS: Transient PAIg and thrombocytopenia can occur following H3N2 infection, while routine vaccination for DA2PP in this group of dogs was not associated with the development of thrombocytopenia or clinically relevant formation of PAIg.

Prognostic potential of inflammatory markers, oxidative status, thrombocyte indices, and renal biochemical markers in neonatal calf diarrhoea-induced systemic inflammatory response syndrome.

The study aimed to assess the prognostic value of inflammatory markers, indicators of oxidative stress, thrombocyte indices, and renal biochemical markers in neonatal calf diarrhoea (NCD) induced by systemic inflammatory response syndrome (SIRS) upon admission. A prospective, observational, and case-control study was conducted on 56 calves diagnosed with NCD. Mean concentrations of interleukin-6 (IL-6), malondialdehyde (MDA), glutathione (GSH), mean platelet volume (MPV), platelet distribution width (PDW), blood urea nitrogen (BUN), and creatinine (Crea) were measured. Furthermore, the neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR) were also calculated for SIRS survivors [SIRS (survivor)] and non-survivors [SIRS (non-survivor)] induced by NCD. A prognostic cut-off value for predicting the prognosis of the SIRS's induced by NCD was obtained via receiver operating characteristic (ROC) curve analysis. Upon admission, the SIRS (non-survivor) calves had significantly higher (P < .001) average levels of IL-6, MDA, BUN, Crea, MPV, and PDW compared to the SIRS (survivor) calves and significantly lower (P < .001) average levels of GSH. Despite an apparent increase in the NLR and PLR values of calves diagnosed with SIRS, no significant difference was found between the survival and non-survivor SIRS cases. Positive predictive values (PPVs) for survival were determined as 100 %, 100 %, 80 %, 100 %, 80 %, and 80 %, respectively, using cut-off values of IL-6 (≤259.67 ng/L), MDA (≤2.87 nmol/mL), MPV (≤12.5 fL), PDW (≤34.25 %), BUN (≤168.3 mg/dL), and Crea (≤2.11 mg/dL). The determined threshold values are those obtained upon admission to the hospital. Based on the sensitivity, specificity, and PPVs derived from the ROC analysis, it has been concluded that IL-6, MDA, MPV, PDW, BUN, and Crea are the most relevant biomarkers used for predicting the prognosis of NCD-induced SIRS in calves. Furthermore, it is also noteworthy that IL-6 exhibited the highest effectiveness among all biomarkers.

Thromboelastographic evaluation in dogs with Asian pit viper (Gloydius) envenomation.

The objective of this study was to investigate the thromboelastography (TEG) variables and platelet count after Asian pit viper (Gloydius) envenomation in dogs compared with healthy control dogs. Ten dogs with snake envenomation and twenty healthy dogs were included. There was a significant decrease in G (P=0.017), maximum amplitude (MA) (P=0.012), angle value (P=0.041), platelet count (P<0.001, as well as an increase in K value (P=0.034) and R value (P=0.007) in dogs with snake envenomation. The results of this study revealed that dogs with Asian pit viper (Gloydius) envenomation showed a hypocoagulable state compared with healthy dogs. Our findings may support the use of TEG for diagnosing and monitoring coagulopathy after Asian pit viper (Gloydius) envenomation in dogs.

Platelet count and MCHC as independent prognostic markers for feline mammary carcinomas.

Mammary neoplasms are common in felines species and represent a significant disease for its unfavorable prognosis. Changes in the blood count and serum biochemical profile of these patients have potential as non-invasive prognostic markers prior to mastectomy, however, they are poorly described in literature. In this study univariate and multivariate analyses were performed using these factors to determine the effect of each parameter on the one-year survival time after the surgical procedure in these animals. The median overall survival (OS) and the disease-free survival (DFS) were 365 and 242 days, respectively. In univariate analysis, values within the reference range of monocyte, platelet and creatinine counts were identified as significant prognostic factors for OS and only creatinine was significant for DFS (P < 0.05). In the multivariate analysis, platelets and mean corpuscular hemoglobin concentration (MCHC) remained independent prognostic factors for OS. The results presented suggest that monocytes, platelets and creatinine may be important non-invasive pre-surgical prognostic markers, and that platelet count and MCHC are independent prognostic markers for feline mammary carcinomas (FMC). The correlation between such alterations is of important relevance for veterinary oncology, and prospective studies are needed to validate their clinical use and that platelet count and MCHC are independent prognostic markers for FMC. The results found in this study can also be studied in human medicine, regarding blood markers in human breast cancer (HBC).

Performance of the Sysmex XN-V hematology analyzer in determining the immature platelet fraction in dogs: A preliminary study and reference values.

BACKGROUND: Immature platelets (IPs) are newly formed platelets released into circulation that have been demonstrated as good markers of thrombopoiesis. Although many flow cytometric and fully automated-based methods are available, the latest Sysmex XN-V hematology analyzer for veterinary use is equipped with a specific fluorescent platelet channel (PLT-F) that detects platelets using a platelet-specific dye. OBJECTIVES: The aims of this study were to evaluate the performance of the Sysmex XSN-1000 V in determining the IPF (immature platelet fraction) and other selected PLT-F channel parameters and to propose IPF reference intervals (RIs) for canine blood samples. METHODS: Canine EDTA blood samples were analyzed on the Sysmex XN-1000 V to assess linearity, imprecision, carryover, stability, and the effect of platelet clumping on selected platelet parameters from the PLT-F channel. We also reported the de novo generated RIs for the IPF in dogs. RESULTS: Imprecision was acceptable (CV <10%) for all parameters except for the absolute IPF values (IPF#), in which the reproducibility was 12.15% for the normal-low concentration samples. Linearity and carryover were excellent for all variables. Relative IPF values (IPF %) and IPF# remained stable for both storage conditions for up to 48 hours; however, a nonsignificant progressive increase in these parameters was observed from 12 hours at 4°C. We observed a statistical increase in IPF% and IPF# and a statistically significant decrease in PLT-F counts after intentional in vitro platelet aggregation. RIs were generated for all reference samples (n = 69) and for samples with (n = 25) or without (n = 44) platelet clumps. CONCLUSIONS: The performance of the new PLT-F channel-derived variables for dogs was excellent. Specific RIs for IPF should be used when platelet aggregates are present.

Thrombocytosis in 158 cats (2011-2018).

OBJECTIVES: Thrombocytosis is an uncommon hematologic abnormality that is associated with various physiologic, metabolic, inflammatory and neoplastic conditions in people and dogs. Thrombocytosis is not a well-described abnormality in cats. The objective of this study was to classify thrombocytosis in cats based on underlying disease processes and severity, and to compare this with a control population of cats. METHODS: A retrospective study was conducted by reviewing the medical records of cats with increased (>600 × 103/µl; thrombocytosis group) and normal (200-600 × 103/µl; 2:1 age-matched control group) platelet counts between 2011 and 2018. Platelet counts were estimated based on blood smear assessment in all cats. Cats were classified by the severity (mild, moderate or marked) of thrombocytosis. Diagnoses were recorded for all cases, and were classified broadly into either neoplasia, endocrine or inflammatory disease. RESULTS: In total, 158 cats were identified with thrombocytosis, with 315 cats in the control group. Non-neoplastic inflammatory disease was the most common diagnosis in both groups (54.4% in cats with thrombocytosis and 56.2% in controls; P = 0.77); however, gastrointestinal diseases were more common in cats with thrombocytosis (75.6%) when compared with controls (34.5%; P <0.0001). Neoplasia was diagnosed more frequently in cats with thrombocytosis (44.3%) compared with the control group (25.4%; P <0.0001). Round cell tumor was the most common neoplasia diagnosis in both groups, but gastrointestinal and multicentric lymphoma were diagnosed more frequently in cats with thrombocytosis compared with control cats. No association between the severity of thrombocytosis and etiology was identified. CONCLUSIONS AND RELEVANCE: Thrombocytosis in cats is more commonly associated with gastrointestinal, hepatobiliary or immune-mediated diseases when compared with a control population. Neoplasia, especially multicentric and gastrointestinal lymphoma, was more commonly diagnosed in cats with thrombocytosis when compared with control cats.

Extended sample storage for platelet function testing in healthy dogs.

BACKGROUND: Platelet function testing is important for monitoring the effects of antiplatelet therapy but is not readily used due to time constraints for testing and the need for specialized equipment. OBJECTIVES: This study evaluated the effects of various storage methods on selected platelet function tests to determine if delayed platelet function testing is feasible in canine blood samples. Our hypotheses were that platelet function would not decline during storage and, thus, no differences in test results would be found over time. METHODS: Thirteen healthy dogs were studied. Citrated blood samples were tested with a Platelet Function Analyzer-200 (PFA), which mimics high-shear conditions, using P2Y and CADP cartridges, after being held at room temperature for 2 h and refrigerated for 24 and 48 h. Plateletworks (PW), which measures aggregation based on platelet counting, was performed on an optical hematology analyzer using 10-min-old native samples, citrated samples held at room temperature for 3-4 h and refrigerated for 24 and 48 h, and samples stored in the preservative solution, AGGFix, up to 7 days. RESULTS: PFA closure times increased with storage, especially with the P2Y cartridge. Median aggregation with fresh PW was 94%, and this was maintained at all time points (range of median values 88%-94%). Most samples showed decreased, yet still robust (>70%), aggregation with longer storage. Spontaneous aggregation in citrate was noted in most dogs. AGGFix stabilized platelet aggregates to allow for delayed testing. CONCLUSIONS: Delayed platelet function testing is feasible, but ranges of expected values may differ from tests using fresh samples.

Lymphopenia predicts reduced survival in canine hepatocellular carcinoma.

Platelet to lymphocyte ratio (PLR) is a prognostic marker in human hepatocellular carcinoma (HCC) however, its utility in canine HCC has not been explored. The aim of the study was to determine if PLR could predict survival outcomes in 42 dogs with HCC. PLR was not a significant predictive factor (p = 0.15) but lymphopenia alone was significantly correlated with a reduced probability of survival (p = 0.024). Further studies are needed to evaluate if peripheral lymphocyte count mirrors that of the tumor microenvironment in canine HCC.

Reference interval for the C-ACT activated clotting time test in healthy dogs using a water bath and manual assessment of clot formation.

AIMS: To establish a reference range for the canine C-ACT activated clotting time (ACT) test using a water bath and visual clot assessment technique. METHODS: Healthy, privately owned dogs (n = 48) were prospectively recruited to the study. Blood samples were collected via direct jugular venipuncture for complete blood count, serum biochemistry analysis and measurement of prothrombin time (PT) and activated partial thromboplastin time (aPTT). Five animals with major abnormalities or who became agitated during phlebotomy were excluded. For the 43 remaining animals, 2 mL of blood was collected via the cephalic vein and added directly to a C-ACT tube that was shaken vigorously before being placed in a water bath at 37°C. Tubes were visually assessed for clot formation and C-ACT was recorded in seconds when the magnet within the tube lodged in the clot. RESULTS: The nonparametric reference interval (capturing the central 95% of the data) was 50-80 seconds, with a 90% CI for the lower limit of 50-55 seconds and a 90% CI for the upper limit of 75-80 seconds. The C-ACT ACT test had a positive correlation with aPTT (0.42; 95% CI = 0.13-0.64). There was no evidence of a correlation between C-ACT ACT and age, weight, PT, haematocrit, white blood cell count, platelet count or total protein. CONCLUSIONS AND CLINICAL RELEVANCE: The results of this study suggest that the normal reference interval for ACT in dogs using C-ACT tubes in a 37°C water bath is 50-80 seconds. Care should be taken extrapolating the results of this study to the general population, as the smaller study design had less control for confounders than a larger study. However, when using the described analytical methods, C-ACT tube ACT test results >80 seconds should be considered prolonged in dogs and should prompt further investigation.

Dose-dependent effect of canine lyophilized platelet on an in vitro hemodilution model.

The transfusion of stored platelets has emerged as an efficient method for treating dogs with thrombocytopenia. However, the availability of fresh platelets is limited in veterinary medicine due to demanding storage conditions. Lyophilized platelets have long shelf lives and can be easily stored, increasing their accessibility for thrombocytopenic dogs. Due to the lack of research and information on the dose effect, canine lyophilized platelets are used at a clinical dosage without research-based evidence. This study was to evaluate the dose effect of lyophilized canine platelets on blood coagulability. Three different concentrations of lyophilized canine platelets were added to in vitro hemodilution blood model, increasing the platelet count by 25, 50, and 100 × 106/ml and coagulation profiles were analyzed. The coagulability was evaluated via the plasma fibrinogen concentration, coagulation time, thromboelastography (TEG), and platelet function analyzer (PFA). Higher concentrations of lyophilized platelets showed dose-dependent association with decreased aPTT and R-time of TEG and increased alpha angle and MA of TEG. These results showed the potential that the higher dose of canine lyophilized platelets better improve blood coagulability than the standard dose and provided the basis for further safety and clinical studies.

Contribution of Hemogram Plan in the Horse's Clinical Evaluation.

The interpretation of the blood count is essential to help the equine clinician in the diagnosis, prognosis, patient management, and control of equine diseases. Hematologic alterations often reflect the condition of the individual or an overall response to a pathological situation. A thorough clinical examination of the patient is essential to correctly interpret the hematological results. The most common abnormalities in the erythrogram are mainly anemia and polycythemia. The frequent causes of anemia in horses are acute and chronic blood loss, hemolytic anemia, and anemia caused by chronic disease. Evaluation of leukogram, including a total white cell count, a differential cell count, absolute numbers of specific leukocytes can help identify abnormalities that may suggest specific diseases such as a viral or bacterial infection, inflammatory disorders or even a neoplastic process. The platelet count is most often used to monitor or diagnose conditions that cause too much bleeding related with thrombocytopenia; it can be due to multiple mechanisms such as reduction of thrombopoiesis (myeloptisis, myelofibrosis, myeloproliferative disease, and idiopathic medullary aplasias or due to the effect of mielosuppresive drugs), increased peripheral destruction of platelets (immune mediated thrombocytopenia), consumption (dissemined intravascular coagulation) sequestration of the spleen and loss of platelets by idiopathic origin.

Retrospective evaluation of fresh platelet concentrate administration in dogs: Patient characteristics, outcomes, and transfusion practices in 189 transfusion episodes (2008-2019).

OBJECTIVE: To describe patient characteristics, underlying disease processes, clinical outcomes, transfusion dose and type (therapeutic or prophylactic), platelet count changes, and adverse events associated with platelet concentrate (PC) administration in dogs. DESIGN: Retrospective study. SETTING: University teaching hospital. ANIMALS: A total of 149 dogs, representing 189 PC transfusion episodes. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: In this population, 39 of 149 dogs (26.2%) were diagnosed with primary immune-mediated thrombocytopenia, 22 of 149 (14.8%) had decreased bone marrow production, 12 of 149 (8.0%) received PC during a massive transfusion, 3 of 149 (2.0%) had congenital thrombocytopathia, 59 of 149 (39.6%) had severe thrombocytopenia of other causes, and 14 of 149 (9.4%) underwent transfusion for miscellaneous causes without a documented severe thrombocytopenia. In 117 of 149 dogs (78.5%), >1 site of hemorrhage was noted. The most common sites of hemorrhage were the gastrointestinal (GI) tract in 89 of 149 (59.7%) and the skin in 78 of 149 (52.3%). Overall survival to discharge was 59.1% (88/149). The median PC dose was 0.8 units per 10 kg of body weight per transfusion episode (range: 0.2-6.7). Of 189 episodes, 29 of 189 (15.7%) were prophylactic, and 158 of 189 (83.6%) were therapeutic. For 99 of 189 transfusion episodes, paired pre- and postplatelet counts were available within 24 hours. The median platelet count change was 5.0 × 109 /L (5000/µL; range: -115 × 109 /L to 158 × 109 /L [-115,000 to 158,000/µL]); the posttransfusion platelet count was significantly higher than pretransfusion (P < 0.0001). The increase in platelet count after transfusion was greater in the prophylactic group than the therapeutic group (P = 0.0167). Transfusion reactions were suspected during 2 of 168 episodes (1.2%). CONCLUSIONS: Immune-mediated thrombocytopenia was the most common disease process that resulted in PC transfusion. PC was more frequently administered to animals with active hemorrhage rather than prophylactically, and most dogs had evidence of hemorrhage in multiple organ systems, particularly the GI tract and skin. PC transfusions typically appeared safe, and the median platelet count increased after transfusion.

Amikacin disaggregates platelet clumps in EDTA blood samples from cats and dogs when added postcollection.

BACKGROUND: Pseudothrombocytopenia may lead to the erroneous diagnosis of thrombocytopenia, resulting in unnecessary testing and treatment. The addition of exogenous substances to blood samples prior to collection has been shown to mitigate platelet (PLT) clumps in blood samples. Postcollection additives aiming to disaggregate PLT clumps have been largely unexplored. OBJECTIVES: We aimed to determine if the addition of amikacin to blood samples postcollection aids in the disaggregation of PLT clumps in cats and dogs. METHODS: For this prospective study, EDTA-collected blood samples from 28 cats and 17 dogs were obtained from a hospital population at UC Davis Veterinary Medical Teaching Hospital. Samples had PLT clumps detected on blood smears and thrombocytopenia per analyzer count. Amikacin was added to samples postcollection, and an additional CBC was performed. Flow cytometry was performed to assess PLT-fibrinogen binding in amikacin-treated aliquots. RESULTS: PLT-clumped samples treated with amikacin significantly increased PLT numbers by 134% and decreased mean platelet volume (MPV) values by 14% (P ≤ 0.0001) in cats, and increased PLT numbers by 32% (P = 0.04) and increased MPV values by 9% (P = 0.02) in dogs. Mean cell volume (MCV) slightly increased (<4%) for both species. No other CBC parameters were substantially affected by the addition of amikacin. Flow cytometry showed decreased PLT-fibrinogen binding in the majority of cats but was not significant (P > 0.05). CONCLUSIONS: Adding amikacin to PLT-clumped blood samples postcollection may be a convenient solution for pseudothrombocytopenia in cats and dogs. Future studies are needed to elucidate the mechanism of amikacin and its effectiveness under different storage conditions. This is the first reported use of amikacin postcollection to disaggregate PLT clumps in blood samples from animals.