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Stored canine plasma
Advances
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tory for conventional and advanced coagulation assays, it is important to know the correct procedures for handling and shipping. In one study, reliable prothrombin times (PT) and activated partial thromboplastin times (aPTT) results were obtained on canine plasma refrigerated for up to 48 hours after collection, regardless of whether or not the plasma was separated immediately. In another study, the recommendation for performing coagulation factor analysis within 24 hours of sample collection was based on the instability of canine factor VIII with storage at 4oC. However, the basis of recommendations in many textbooks is unclear, and recommendations vary widely. Objectives To evaluate the stability of individual coagulation factors, clotting times, and other parameters of hemostasis in stored canine plasma. Procedure Citrated plasma samples were obtained from 21 dogs. Prothrombin time, aPTT, fibrinogen concentration, and factor I, II, V, VII, VIII, IX, X, XI, and XII activities were measured. Antithrombin (AT) activity and D-dimer concentration were also measured. Samples were measured once daily for 2 or 4 consecutive days following storage at room temperature or 4oC, respectively. Results Storage time at either temperature had no effect on PT, factor II, V, VII, X, or XII activities, D-dimer concentration, or AT activity. In contrast, aPTT was significantly prolonged after 72 and 96 hours at 4oC. Fibrinogen concentration was decreased after 48 hours at room temperature. The activities of factors VIII and IX were decreased after 48, 72, and 96 hours at 4oC. Factor XI activity was decreased after 72 hours at 4oC.
Stored Canine Plasma
Author Conclusion Storage of canine plasma for 2 days at room temperature does not have a significant effect on hemostasis test results, except for a slight decrease in fibrinogen concentration. In contrast, aPTT and factors VIII, IX, and XI were unstable in refrigerated plasma after 48 or 72 hours of storage.
Background When sending blood samples to a labora-
Inclusions Two tables, 14 references.
Clinical Pathology
Editor Annotation Hemostasis testing in the dog has been a concern for many years. Many clinical pathologists have encouraged clinicians to use their local medical hospital in determining coagulation parameters, since it appeared that clotting factors were very labile and required rapid testing. This study reported that storage of plasma for 2 days at room temperature did not significantly affect the hemostatic parameters, except for a slight decrease in fibrinogen after 48 hrs. Earlier studies had suggested that at 20oC, the prothrombin time was prolonged. This group confirmed the fact that most of the factors for common clotting determinations can be preserved at room temperature. Whether this is true if plasma is exposed to heat needs to be further evaluated. But in most cases where samples can be appropriately cooled and shipped to a veterinary laboratory, these samples should result in accurate values. There may be a slight variation, but generally pathologic changes should be identified. Thus, this should give practitioners that have to ship samples to a distant laboratory confidence that accurate results can be obtained with shipped samples. (LDM) Furlanello T, Caldin M, Stocco A, et al. Stability of stored canine plasma for hemostasis testing. Vet Clin Path 2006;35:204-207.
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tory for conventional and advanced coagulation assays, it is important to know the correct procedures for handling and shipping. In one study, reliable prothrombin times (PT) and activated partial thromboplastin times (aPTT) results were obtained on canine plasma refrigerated for up to 48 hours after collection, regardless of whether or not the plasma was separated immediately. In another study, the recommendation for performing coagulation factor analysis within 24 hours of sample collection was based on the instability of canine factor VIII with storage at 4oC. However, the basis of recommendations in many textbooks is unclear, and recommendations vary widely. Objectives To evaluate the stability of individual coagulation factors, clotting times, and other parameters of hemostasis in stored canine plasma. Procedure Citrated plasma samples were obtained from 21 dogs. Prothrombin time, aPTT, fibrinogen concentration, and factor I, II, V, VII, VIII, IX, X, XI, and XII activities were measured. Antithrombin (AT) activity and D-dimer concentration were also measured. Samples were measured once daily for 2 or 4 consecutive days following storage at room temperature or 4oC, respectively. Results Storage time at either temperature had no effect on PT, factor II, V, VII, X, or XII activities, D-dimer concentration, or AT activity. In contrast, aPTT was significantly prolonged after 72 and 96 hours at 4oC. Fibrinogen concentration was decreased after 48 hours at room temperature. The activities of factors VIII and IX were decreased after 48, 72, and 96 hours at 4oC. Factor XI activity was decreased after 72 hours at 4oC.
Stored Canine Plasma
Author Conclusion Storage of canine plasma for 2 days at room temperature does not have a significant effect on hemostasis test results, except for a slight decrease in fibrinogen concentration. In contrast, aPTT and factors VIII, IX, and XI were unstable in refrigerated plasma after 48 or 72 hours of storage.
Background When sending blood samples to a labora-
Inclusions Two tables, 14 references.
Clinical Pathology
Editor Annotation Hemostasis testing in the dog has been a concern for many years. Many clinical pathologists have encouraged clinicians to use their local medical hospital in determining coagulation parameters, since it appeared that clotting factors were very labile and required rapid testing. This study reported that storage of plasma for 2 days at room temperature did not significantly affect the hemostatic parameters, except for a slight decrease in fibrinogen after 48 hrs. Earlier studies had suggested that at 20oC, the prothrombin time was prolonged. This group confirmed the fact that most of the factors for common clotting determinations can be preserved at room temperature. Whether this is true if plasma is exposed to heat needs to be further evaluated. But in most cases where samples can be appropriately cooled and shipped to a veterinary laboratory, these samples should result in accurate values. There may be a slight variation, but generally pathologic changes should be identified. Thus, this should give practitioners that have to ship samples to a distant laboratory confidence that accurate results can be obtained with shipped samples. (LDM) Furlanello T, Caldin M, Stocco A, et al. Stability of stored canine plasma for hemostasis testing. Vet Clin Path 2006;35:204-207.