Delayed double reading of whole blood clotting test (WBCT) results at 20 and 30 minutes enhances diagnosis and treatment of viper evenomation

The whole blood clotting test (WBCT) is a simple test of coagulation that is often used in the assessment, diagnosis, and therapeutic monitoring of snakebite patients in sub-Saharan Africa. WBCT requires only a clean glass tube and several milliliters of venous blood and is ideal for use in poorly equipped health centers throughout the rural areas where 95% of snakebites occur. However, questions surrounding the accuracy and reliability of the test remain unanswered due to variations in testing conditions and a lack of comparative research with which to validate them. This is the first study to evaluate WBCT results at both 20-min (WBCT20) and 30-min (WBCT30) reading times in the same group of snakebite patients. Methods In order to define the best reading time, the authors compared the results of serial WBCT evaluation at both 20 and 30 min after collection in 23 patients treated for snake envenomation in Bembèrèkè, northern Benin. Results WBCT results were identical at both reading times in patients without coagulopathy or when coagulation was restored permanently following a single dose of antivenom. Out of 17 patients with coagulopathy, 14 showed discrepancies between WBCT20 and WBCT30 results in at least one pair of serial evaluations. These could be completely contradictory results (e.g. normal clot at WBCT20 and no clot at WBCT30) or a marked difference in the quality of the clot (e.g. no clotting activity at WBCT20 and an unstable partial clot at WBCT30)...(AU)

Delayed double reading of whole blood clotting test (WBCT) results at 20 and 30 minutes enhances diagnosis and treatment of viper evenomation

The whole blood clotting test (WBCT) is a simple test of coagulation that is often used in the assessment, diagnosis, and therapeutic monitoring of snakebite patients in sub-Saharan Africa. WBCT requires only a clean glass tube and several milliliters of venous blood and is ideal for use in poorly equipped health centers throughout the rural areas where 95% of snakebites occur. However, questions surrounding the accuracy and reliability of the test remain unanswered due to variations in testing conditions and a lack of comparative research with which to validate them. This is the first study to evaluate WBCT results at both 20-min (WBCT20) and 30-min (WBCT30) reading times in the same group of snakebite patients. Methods In order to define the best reading time, the authors compared the results of serial WBCT evaluation at both 20 and 30 min after collection in 23 patients treated for snake envenomation in Bembèrèkè, northern Benin. Results WBCT results were identical at both reading times in patients without coagulopathy or when coagulation was restored permanently following a single dose of antivenom. Out of 17 patients with coagulopathy, 14 showed discrepancies between WBCT20 and WBCT30 results in at least one pair of serial evaluations. These could be completely contradictory results (e.g. normal clot at WBCT20 and no clot at WBCT30) or a marked difference in the quality of the clot (e.g. no clotting activity at WBCT20 and an unstable partial clot at WBCT30)...

Valores de Referência para tempos de coagulação em uma população de cães de Porto Alegre, RS, Brasil / Reference values for coagulation time of dogs in Porto Alegre, RS, Brazil

Background: Prothrombin time (PT) and activated partial thromboplastin time (PTT) are screening tests for coagulopathies in dogs. Both tests measure the clotting ability by the activation of different parts of the coagulation cascade. These tests vary widely in terms of reference parameters, mainly due the considerable diversity of reagents and analyzers available. In addition, there are many variations inherent to different populations, and little has been published about coagulation reference parameters for the local dog population. The main objective of the present study was to determine a clotting time reference range of a dog population in Porto Alegre, Rio Grande do Sul, Brazil.Materials, Methods & Results: Hemostatic reference range was determined from citrated plasma of 268 clinically heathy dogs of both genders. The animals did not present bleeding diathesis or thrombocytopenia history. All dogs were previously submitted to clinical examination (cardiopulmonary auscultation, abdominal palpation, and rectal temperature) and laboratory screening (complete blood count, creatinine, albumin, and alanine aminotransferase). PT and PTT of 71 and 258 samples were measured, respectively. Blood samples were collected into 2.7 mL 3.2 % sodium citrate tubes (9 parts blood : 1 part citrate) by vacuum. Blood samples were centrifuged; the plasma was harvested and stored at -30 °C upon analyses. All analyses were performed using the viscosity detection method in semi-automatic coagulometer according to manufacturers guidelines. The reference ranges were determined in accordance with the American Society for Veterinary Clinical Pathology. The PT and PTT reference ranges were between 6.06 to 9.32 s and between 15.25 to 24.57 s, respectively.Discussion: The increased activity of the extrinsic pathway clotting factor generates narrow values in the PT assay, in comparison to PTT results.[...](AU)

Valores de Referência para tempos de coagulação em uma população de cães de Porto Alegre, RS, Brasil / Reference values for coagulation time of dogs in Porto Alegre, RS, Brazil

Background: Prothrombin time (PT) and activated partial thromboplastin time (PTT) are screening tests for coagulopathies in dogs. Both tests measure the clotting ability by the activation of different parts of the coagulation cascade. These tests vary widely in terms of reference parameters, mainly due the considerable diversity of reagents and analyzers available. In addition, there are many variations inherent to different populations, and little has been published about coagulation reference parameters for the local dog population. The main objective of the present study was to determine a clotting time reference range of a dog population in Porto Alegre, Rio Grande do Sul, Brazil.Materials, Methods & Results: Hemostatic reference range was determined from citrated plasma of 268 clinically heathy dogs of both genders. The animals did not present bleeding diathesis or thrombocytopenia history. All dogs were previously submitted to clinical examination (cardiopulmonary auscultation, abdominal palpation, and rectal temperature) and laboratory screening (complete blood count, creatinine, albumin, and alanine aminotransferase). PT and PTT of 71 and 258 samples were measured, respectively. Blood samples were collected into 2.7 mL 3.2 % sodium citrate tubes (9 parts blood : 1 part citrate) by vacuum. Blood samples were centrifuged; the plasma was harvested and stored at -30 °C upon analyses. All analyses were performed using the viscosity detection method in semi-automatic coagulometer according to manufacturer’s guidelines. The reference ranges were determined in accordance with the American Society for Veterinary Clinical Pathology. The PT and PTT reference ranges were between 6.06 to 9.32 s and between 15.25 to 24.57 s, respectively.Discussion: The increased activity of the extrinsic pathway clotting factor generates narrow values in the PT assay, in comparison to PTT results.[...]