Search

Canine coagulation factor VII (FVII) deficiency can be hereditary or acquired and may cause life threatening bleeding episodes if untreated. FVII procoagulant activity can be measured by FVII activity (FVII:C), but assays for measurement of canine specific FVII antigen (FVII:Ag) have not been available to date. In this study, a canine specific ELISA for measurement of FVII:Ag in plasma was developed and validated. The FVII:Ag ELISA correctly diagnosed homozygous and heterozygous hereditary FVII deficiency. Together with activity based assays, such as FVII:C, the FVII:Ag ELISA should be valuable in the diagnosis of hereditary canine FVII deficiency., (Copyright © 2010 Elsevier Ltd. All rights reserved.)

Coagulation tests are often performed in dogs suspected of haemostatic dysfunction and are interpreted according to validated laboratory reference intervals (RIs). Breed specific RIs for haematological and biochemical analytes have previously been identified in Bernese Mountain dogs, but it remains to be determined if breed specific RIs are necessary for haemostasis tests. Activated prothromboplastin time (aPTT), prothrombin time (PT), selected coagulation factors, D-dimers, fibrinogen, von Willebrand factor and thromboelastography (TEG) were analyzed in healthy Bernese Mountain dogs using the CLSI model. Three analytes (aPTT, TEG [MA] and TEG [G]) were different according to the CLSI model. For aPTT the new RI was markedly different (0-100s). Whereas the new intervals for TEG (MA) and TEG (G) may be due to breed related biological variation, the cause of the prolonged RI for aPTT is at present uncertain., (Copyright © 2010 Elsevier Ltd. All rights reserved.)

A template for a scoring system for disseminated intravascular coagulation (DIC) in humans has been proposed by the International Society on Thrombosis and Haemostasis (ISTH). The objective of this study was to develop and validate a similar objective scoring system based on generally available coagulation tests for the diagnosis of DIC in dogs. To develop the scoring system, 100 dogs consecutively admitted to an intensive care unit (ICU) with diseases predisposing for DIC were enrolled prospectively (group A). The validation involved 50 dogs consecutively diagnosed with diseases predisposing for DIC, admitted to a different ICU (group B). Citrated blood samples were collected daily during hospitalisation and diagnosis of DIC was based on the expert evaluation of an extended coagulation panel. A multiple logistic regression model was developed in group A for DIC diagnosis. The integrity and diagnostic accuracy of the model was subsequently evaluated in a separate prospective study at a different ICU (group B) and was carried out according to The Standards for Reporting of Diagnostic Accuracy (STARD) criteria. Thirty-seven dogs were excluded from group A and four from group B due to missing data. Based on expert opinion, 23/63 dogs (37%) had DIC. The final multiple logistic regression model was based on activated partial thromboplastin time, prothrombin time, D-Dimer and fibrinogen. The model had a diagnostic sensitivity and specificity of 90.9% and 90.0%, respectively. The diagnostic accuracy of the model was sustained by prospective evaluation in group B (sensitivity 83.3%, specificity 77.3%). Based on commonly used, plasma-based coagulation assays, it was possible to design an objective diagnostic scoring system for canine DIC with a high sensitivity and specificity., (Copyright 2009 Elsevier Ltd. All rights reserved.)

Haematological and biochemical parameters were studied prospectively in 48 dogs naturally infected with Angiostrongylus vasorum in a primary care setting. Samples for analysis were obtained when treatment was started and 42days afterwards. Prior to treatment, 21% of affected dogs exhibited eosinophilia, whereas increased total white blood cell (WBC) counts and neutrophilia were observed in only 4.2%. WBC counts and concentrations of neutrophils, eosinophils and monocytes decreased significantly from days 0 to 42, indicating that, even in dogs without elevated absolute blood values, a low grade inflammatory response may be present in dogs with A. vasorum infection. Biochemical changes (especially an increase in serum globulins and a decrease in serum fructosamine) were in agreement with the findings of other studies. The results show that the diagnosis of canine angiostrongylosis should not be excluded based on unremarkable haematological and blood biochemical parameters. They also support our recent finding that a low serum fructosamine concentration may be associated with infection with A. vasorum.

The ability of a laboratory assay to correlate to clinical phenotype is crucial for the accurate diagnosis and monitoring of haemostasis and is therefore challenging with currently used routine haemostasis assays. Thromboelastography (TEG) is increasingly used to evaluate haemostasis in humans and may well be of value in the workup of dogs suspected of having a haemostatic disorder. This study was undertaken to evaluate prospectively how tissue factor (TF) activated TEG correlated to clinical signs of bleeding in dogs, compared to a routine coagulation profile. A prospective case-control study was performed over a 2 year period from 2004-2006. Eligible dogs were those where the primary clinician requested a coagulation profile to evaluate haemostasis. The dogs were simultaneously evaluated with a TF-activated TEG assay. Twenty-seven dogs, characterised as hypo-coagulable based on the TEG parameter G (<3.2 Kdyn/cm(2)), were included in the study as cases. Size matched control groups of TEG normo- (G=3.2K-7.2 Kdyn/cm(2)) and hyper-coagulable (G>7.2 Kdyn/cm(2)) dogs were selected retrospectively from the eligible dogs. For all dogs, clinical signs of bleeding were noted at time of analysis. There were statistically significant differences between all TEG values of hypo- and normo- and hyper-coagulable dogs. Thromboelastography correctly identified dogs with clinical signs of bleeding with a positive predictive value (PPV) of 89% and a negative predictive value (NPV) of 98% based on G alone. In comparison, the coagulation profile had a PPV between 50-81% and a NPV between 92-93% for detection of bleeding, depending on the observer. In conclusion, a TF-activated TEG G value<3.2K dyn/cm(2) correctly identified dogs with clinical signs of bleeding with very high PPV and NPV, irrespective of observer. The findings strongly suggest that TF- activated TEG may be of value in the workup of dogs suspected of having a haemostatic disorder.

Thromboelastography (TEG) may be a valuable supplement to the coagulation assays activated partial thromboplastin time (aPTT), prothrombin time (PT), thrombin time (TT), fibrinogen, antithrombin (AT) and D-Dimer currently used in most clinical pathology laboratories. Allowable imprecision and bias reference limits for analytical tests can be calculated based on measurements of biological variation. No studies to date have examined the effect of biological variation on these haemostasis parameters in the same group of dogs. Plasma samples were collected after a set protocol once weekly for five consecutive weeks from eight healthy dogs (four males and four females) and stored at -80 degrees C until analysis. Randomized duplicate coagulation tests and TEG analyses were performed on all plasma samples within one run. The data were analyzed for outliers and subsequently subjected to nested analysis of variance to obtain the coefficient of analytical, intra-individual and inter-individual variation. From these objective analytical performance standards for imprecision, critical difference, total error and the index of individuality were calculated to assess the utility of conventional population-based reference ranges. All the clotting times (aPTT, PT and TT), fibrinogen, AT and D-Dimer showed a degree of individuality, which may make the use of population-based reference ranges alone an insensitive interpretation criterion, whereas a population-based reference interval seems to be sensitive for interpreting all TEG parameters. Analytical performance standards for imprecision were only met for one of the coagulation assays, whereas all TEG parameters except the alpha angle, alpha achieved this analytical goal.

The objective of the present study was to validate the use of blood collected from an indwelling arterial catheter for analysis of haematological, coagulation and inflammatory parameters in canines compared to venous blood collected directly from the jugular vein. Blood samples were collected from 11 dogs. Agreement between sampling methods was found for neutrophil and monocyte counts, prothrombin time, activated partial thromboplastin time, antithrombin, protein C, factor VIII and C-reactive protein, whereas a statistically significant difference was found for white blood cells, lymphocyte, erythrocyte and platelet counts, haemoglobin, haematocrit, fibrinogen and thrombin time (TT). In conclusion, it is necessary to be aware that results from a complete blood count obtained from canine venous and arterial blood samples may not be comparable. Values for haemostatic parameters from arterial and venous blood samples, with the exception of fibrinogen and TT, were however statistically identical.

The objective was first to evaluate the performance (intra- and inter-assay imprecision, inaccuracy, detection limit and overlap performance) of two different commercially available human C-reactive protein (CRP) immunoturbidimetric assays (TIA) applied to porcine serum CRP; and secondly to investigate inter-laboratory discrepancies and the influence of calibration materials when comparing results. The intra-laboratory performance seemed acceptable for clinical purposes for both assays with excellent overlap performance, acceptable detection limits, no significant inaccuracies and low imprecision. Although a significant discrepancy in the measured CRP levels was observed when comparing results, the methods agreed significantly on diagnostic classification, suggesting a low clinical significance. Both assays performed reliably for the heterologous determination of porcine serum CRP for clinical purposes. The results emphasise the need to establish species-specific standards to decrease inter-laboratory discrepancies.

The objective was to evaluate independently the reliability of a commercially available canine serum interleukin-10 (IL-10) enzyme-linked immunoassay (ELISA) and to investigate canine serum IL-10 concentrations in healthy dogs, in dogs with a naturally-occurring acute phase reaction and in dogs following surgical stimulus by assessing intra- and interassay imprecision, inaccuracy and detection limits. Median (and range) serum IL-10 concentrations (ng/L) in the various groups were as follows: healthy dogs (n=15), 18.9 (11.2-71.5); dogs with pyometra (n=9), 37.9 (12.4-201.8); dogs with angiostrongylosis (n=8), 20.29 (14.3-108.7) and values in dogs following surgical stimulus (n=15), 14.8 (10.7-65.8). The assay measured canine serum IL-10 reliably (intra- and interassay imprecision 4.9-8.3% and 9.9-10.9%, respectively; detection limit 10.7 ng/L with no significant inaccuracy). No significant increases in IL-10 were observed following surgical stimulus and no difference in IL-10 was observed between the diagnostic groups. IL-10 values showed a higher degree of variation in dogs with an inflammatory response, i.e. those with elevated serum C-reactive protein (CRP) concentrations, compared to healthy dogs. As anticipated, healthy dogs had low levels of both analytes, whereas dogs with an acute phase response had IL-10 levels with no clear relationship to CRP concentrations, with observed low IL-10 values even when there was a marked inflammatory response.

The aim of the present study was to evaluate whether equine serum amyloid A (SAA) concentrations could be measured reliably with a turbidometric immunoassay (TIA) developed for use with human serum. Intra- and inter-assay imprecision were evaluated by multiple measurements on equine serum pools. Assay inaccuracy was determined by linearity under dilution. The assay was subsequently used for measuring SAA concentrations in clinically healthy horses, horses with inflammatory diseases, horses with non-inflammatory diseases, and in horses before and after castration. In pools with low, intermediate and high SAA concentrations, the intra-assay imprecisions were 24.4%, 1.6% and 2.1%, and the inter-assay imprecisions were 33.2%, 4.6% and 6.5%. Slight signs of inaccuracy were observed, but these inaccuracies were negligible when considering the large dynamic range of the SAA response. The assay was able to detect the expected difference in SAA levels in different groups of horses. It was also able to demonstrate the expected dynamic changes in SAA after castration. In conclusion, equine SAA concentrations can be measured reliably using the TIA designed for human SAA.