Mean Platelet Volume Artifacts: The Effect of Anticoagulants and Temperature on Canine Platelets (original) (raw)
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Biologic variability and correlation of platelet function testing in healthy dogs
Veterinary Clinical Pathology, 2015
Background: Platelet function tests are influenced by biologic variability, including inter-individual (CV G) and intra-individual (CV I), as well as analytic (CV A) variability. Variability in canine platelet function testing is unknown, but if excessive, would make it difficult to interpret serial results. Additionally, the correlation between platelet function tests is poor in people, but not well described in dogs. Objectives: The aims were to: (1) identify the effect of variation in preanalytic factors (venipuncture, elapsed time until analysis) on platelet function tests; (2) calculate analytic and biologic variability of adenosine diphosphate (ADP) and arachidonic acid (AA)-induced thromboelastograph platelet mapping (TEG-PM), ADP-, AA-, and collagen-induced whole blood platelet aggregometry (WBA), and collagen/ADP and collagen/epinephrine platelet function analysis (PFA-CADP, PFA-CEPI); and (3) determine the correlation between these variables. Methods: In this prospective observational trial, platelet function was measured once every 7 days, for 4 consecutive weeks, in 9 healthy dogs. In addition, CBC, TEG-PM, WBA, and PFA were performed. Results: Overall coefficients of variability ranged from 13.3% to 87.8% for the platelet function tests. Biologic variability was highest for AAinduced maximum amplitude generated during TEG-PM (MA AA ; CV G = 95.3%, CV I = 60.8%). Use of population-based reference intervals (RI) was determined appropriate only for PFA-CADP (index of individuality = 10.7). There was poor correlation between most platelet function tests. Conclusions: Use of population-based RI appears inappropriate for most platelet function tests, and tests poorly correlate with one another. Future studies on biologic variability and correlation of platelet function tests should be performed in dogs with platelet dysfunction and those treated with antiplatelet therapy.
Evaluation of reticulated platelets in dogs
Comparative Haematology International, 1998
Reticulated platelets are immature platelets that have increased ribonucleic acid content. Reticulated platelets were evaluated in the blood of 20 healthy nonthrombocytopenic dogs and 45 thrombocytopenic dogs to dctcrmine if the assay could be used as a non-invasive measure of thrombopoiesis, Reticulated platelets were evaluated by detecting fluorescence of thiazole orangestained platelets using a flow cytometer. Of 45 thrombocytopenic dogs 36 had an increased percentage of reticulated platelets when compared to values for the healthy non-thrombocytopenic dogs. However, none of these dogs had increased total reticulated platelet numbers. Most dogs with an increased percentage of reticulated platelets had disease conditions in which the thrombocytopenia was attributed to destruction or consumption of platelets, whereas, those that did not have an increased percentage of reticulated platelets had conditions associated with decreased thrombopoiesis. However, too few dogs with suspected decreased thrombopoiesis were included in the study to make a conclusion about the capacity of the test to detect decreased platelet production. Results of this study indicate that the percentage of reticulated platelets may be useful as a non-invasive predictor of thrombopoiesis in dogs.
Platelet Function and Therapeutic Applications in Dogs: Current Status and Future Prospects
Animals
Significant progress has been made in the functional characterization of canine platelets in the last two decades. The role of canine platelets in hemostasis includes their adhesion to the subendothelium, activation, and aggregation, leading to primary clot formation at the site of injury. Studies on canine platelet function and advancements in laboratory testing have improved the diagnosis and understanding of platelet-related disorders as well as the knowledge of the mechanisms behind these diseases. This review focuses on the most recent discoveries in canine platelet structure, function, and disorders; and discusses the efficacy of various tests in the diagnosis of platelet-related disorders. With the relatively recent discovery of angiogenetic and reparative effects of growth factors found in platelets, this review also summarizes the use of canine platelet-rich plasma (PRP) alone or in association with stem cells in regenerative therapy. The characterization of proteomic and l...
Density distribution of 51CR-labelled platelets within the circulating dog platelet population
Thrombosis Research, 1973
The density distribution of 51 Cr.labelled platelets was studied in a linear colloidal silica-polyvinylpyrrolidone density gradient and compared with the density distribution of the circulating platelet population. Twenty-four, 48 and 72 hours after labelling of the platelets close correspondence was found between the density distribution of the label and the platelets, These results seem to justify the use of 51Cr-labelled platen lets for turnover studies and for quantitation of platelet deposition in various organs as well as in experimental thrombi.
Kinetics of platelet density subpopulations in splenectomized mongrel dogs
American Journal of Hematology, 1984
Autologous 'Cr-platelet kinetic studies were performed in splenectomized mongrel dogs. Mean survival time of PRP-platelets was 5.4 f 1.5 (SD) days (n = 6). The curves, though slightly curvilinear, showed mostly a linear type of decay, denoting that platelet removal from the circulation is mainly determined by aging of the cells. High-density (HD) and low-density (LD) platelet cohorts were isolated in Stractan gradients from samples drawn daily after infusion of labeled platelets. Specific radioactivity in HD cohorts declined rapidly postinfusion (T% = 1.3 days), but specific radioactivity in LD platelets increased for 2 days and steadily declined for 4 days thereafter (n = 6). Labeled HD platelets, comprising 11.7% of the total population, lived significantly longer in circulation than LD platelets (19.1 % of the total population) (n = 3). The patterns of decay of the radioactivity, however, do not have all the characteristics of pure age-cohort survival curves; 3.7 days after the infusion of labeled HD platelets, the specific radioactivity in LD cohorts was six times higher than on day 1, but attained only 20% of the initial specific radioactivity in HD platelets. After the infusion of labeled LD platelets no radioactivity was recovered in circulating HD cohorts.
Description of a double centrifugation tube method for concentrating canine platelets
BMC Veterinary Research, 2013
Background: To evaluate the efficiency of platelet-rich plasma preparations by means of a double centrifugation tube method to obtain platelet-rich canine plasma at a concentration at least 4 times higher than the baseline value and a concentration of white blood cells not exceeding twice the reference range. A complete blood count was carried out for each sample and each concentrate. Whole blood samples were collected from 12 clinically healthy dogs (consenting blood donors). Blood was processed by a double centrifugation tube method to obtain platelet concentrates, which were then analyzed by a flow cytometry haematology system for haemogram. Platelet concentration and white blood cell count were determined in all samples. Results: Platelet concentration at least 4 times higher than the baseline value and a white blood cell count not exceeding twice the reference range were obtained respectively in 10 cases out of 12 (83.3%) and 11 cases out of 12 (91.6%). Conclusions: This double centrifugation tube method is a relatively simple and inexpensive method for obtaining platelet-rich canine plasma, potentially available for therapeutic use to improve the healing process.
Evaluation of time and temperature storage in platelet counts in blood samples of dogs
Comparative Clinical Pathology, 2019
The reliability of platelet counts obtained by different methods following different storage times/conditions is not well defined. The aim was to evaluate temporal changes in platelet count of canine blood samples submitted to two thermal storage conditions using three techniques of platelet counting. Blood samples were obtained from 40 dogs aged between 6 months and 12 years. Blood samples were collected by jugular venipuncture, separated into two aliquots, and stored in EDTA tubes: one kept at room temperature (RT group) and the other kept under refrigeration (RE group). The platelet count was performed using the hemocytometer method, blood smear counting, and automated counting immediately after blood collection (M0) and 30 min and 1, 2, 4, 6, and 24 h later in both groups. The platelet parameters provided by the electronic counter were also obtained. There was a significant difference in platelet counts between the manual and automated methods when the samples were processed 24 h after sample collection. The refrigerated samples remained with closer platelet values of the previous samples for longer than those stored at room temperature. The analysis of platelet parameters loses its validity when the samples are stored for more than 6 h. The plaquetogram is reliable when the sample is processed up to 4 h after collection, regardless of the storage method. The timing of the platelet count should not exceed 6 h after collection for refrigerated samples and 4 h for samples stored at room temperature, for all counting methods.
Factors Affecting Platelet Concentration in Platelet Concentrates from Canine Blood Donors
Journal of Veterinary Internal Medicine
Background: Physiologic factors in dogs that might contribute to enhanced platelet yield in platelet concentrates (PCs) are largely unknown. Objective: To determine whether individual differences in weight, age, preprocessing blood chemistry, and CBC variables predict the final platelet concentrations in PCs. Our hypotheses were (1) increased lipemic indices would be positively associated with increased platelet concentrations in PCs and (2) increased preprocessing platelet concentrations would be associated with higher platelet concentrations in the PCs. Animals: All blood donation records of dogs from February 2, 2009 through April 1, 2015 at the University of California-Davis Veterinary Blood Bank were examined with 104 cases included in this study. Methods: In this retrospective study, data were collected from medical records of canine blood donors. Records were reviewed for internal consistency and accuracy and subjects were included in the study if donor screening and donation occurred on the same day and a viable PC was obtained. Univariate and multivariable regressions were used to test the impact that each variable had on the final platelet concentration in PCs. Results: Final platelet concentration in PCs was positively associated with the predonation CBC platelet values (P < .001), lipemic index (P = .01), and phosphorous levels (P = .001). Collectively these 3 variables explained 29% of the variance in platelet concentrations in PCs. Conclusions and clinical importance: Future prospective studies are required to determine if canine blood donations from dogs with lipemia yield PCs with higher platelet concentrations without negatively affecting other blood components.
Veterinary Clinical Pathology, 2008
Background: Many Cavalier King Charles Spaniel (CKCS) dogs are affected by an autosomal recessive dysplasia of platelets resulting in fewer but larger platelets. The IDEXX Vet Autoread (QBC) hematology analyzer directly measures the relative volume of platelets in a blood sample (plateletcrit). We hypothesized that CKCS both with and without hereditary macrothrombocytosis would have a normal plateletcrit and that the QBC results would better identify the total circulating volume of platelets in CKSC than methods directly enumerating platelet numbers. Objectives: The major purpose of this study was to compare the QBC platelet results with platelet counts from other automated and manual methods for evaluating platelet status in CKCS dogs. Methods: Platelet counts were determined in fresh EDTA blood from 27 adult CKCS dogs using the QBC, Sysmex XT-2000iV (optical and impedance), CELL-DYN 3500, blood smear estimate, and manual methods. Sysmex optical platelet counts were reanalyzed following gating to determine the number and percentage of normal-and large-sized platelets in each blood sample. Results: None of the 27 CKCS dogs had thrombocytopenia (defined as o 164 Â 10 9 platelets/L) based on the QBC platelet count. Fourteen (52%) to 18 (66%) of the dogs had thrombocytopenia with other methods. The percentage of large platelets, as determined by regating the Sysmex optical platelet counts, ranged from 1% to 75%, in a gradual continuum. Conclusions: The QBC may be the best analyzer for assessing clinically relevant thrombocytopenia in CKCS dogs, because its platelet count is based on the plateletcrit, a measurement of platelet mass.