Meet The Author
October 2025
Claire Sharp BSc, BVMS(Hons), MS, DACVECC
I am the proud mother of a longhaired Dachshund called Koda - I had never imagined being a small dog owner, but I love him dearly. Scuba diving is my second passion to ECC and manta rays + sharks are my favourite animals to encounter underwater.
The hemostatic profile of cold-stored whole blood from non-greyhound and greyhound dogs over 42 days
Cooper JL, Sharp CR, Boyd CJ, Claus MA, Rossi G
The Study Background
There has been a resurgence of interest in the use of cold stored whole blood (SWB) for human trauma patients given that it provides red cells and plasma in physiologic ratios. Additionally, while classically considered that the platelets became non-functional in cold SWB, recent evidence suggests that they provide a phospholipid membrane on which secondary hemostasis can occur and do contribute to clot formation after transfusion. This information, in addition to cold SWB being the most accessible blood product for many veterinarians, prompted us to study the hemostatic profile of this product in dogs.
What is the primary knowledge gap your study aims to address?
The hemostatic capacity of whole blood, cold stored for 42 days following collection from greyhound and non-greyhound blood donors including the contribution made by the various clotting factors and platelets.
The Study Design
This was a prospective ex vivo study that used cold SWB from 10 greyhound and 10 non-greyhound blood donors. The primary objective of the study was to characterize changes in the viscoelastic properties, prothrombin time (PT) and activated partial thromboplastin time (aPTT), coagulation factor (F) activities (FII, FV, FVII, FVIII, FIX, FX, FXIII antigen [FXIII:Ag], vWF:Ag, fibrinogen, platelet closure time (non-greyhounds only), and estimated manual platelet count (GD only) of canine whole blood stored at 4◦C for 42 days. The secondary objective was to compare the ROTEM (rotational thromboelastometry) alpha-angle and maximum clot firmness (MCF), as well as coagulation factor activities and fibrinogen concentration changes between greyhound and non-greyhound cold SWB over the storage period.
What are the main study results?
ROTEMs from greyhound SWB were comparatively more hypocoagulable than non-greyhound SWB at all timepoints. While there was quite a bit of variation between breed groups, individual ROTEM parameters, and intrinsic vs. extrinsic thromboelastometry, in general ROTEM parameters decreased to <50% of baseline within 2-4 weeks. Activity of coagulation factors II, VII, IX, and X (the vitamin K dependent factors) remained above 50% of normal for the duration of the study period in both greyhound and non-greyhound SWB, despite greyhound SWB having lower activity of FII, V, and IX than non-greyhound SWB. As such, cold SWB is a suitable product for transfusion to dogs following hemorrhage from anticoagulant rodenticide induced coagulopathy. FVIII was the least stable in both breed groups, with a rapid decline in activity within the first week of storage, suggesting that cold SWB is not a suitable product for transfusion to dogs with hemophilia A. Greyhound SWB had greater vWF:Ag than non-greyhound SWB, remaining above 50% activity for 42 days, while non-greyhound SWB vWF:Ag declined below 50% activity after 21 days, suggesting that breed and storage duration affect the utility of SWB for transfusion to dogs with von Willebrand disease. Non-greyhound SWB had significantly higher fibrinogen concentrations than that from greyhounds, remaining within reference interval for the first 21 days of cold storage. Regarding information about the platelet contribution to the clot - the platelet closure time measured with a platelet function analyser in non-greyhound SWB was above the device limit by day 7 of storage, but the platelet count (measured in greyhound SWB) did not change during 42 days of storage. As you might appreciate our paper contains lots of detail, and a lot of nuance. If hospitals are stocking dog cold SWB we would recommend taking a closer look at our data to devise recommendations for your practice about the ideal duration of storage for the specific types of cases that you use blood for.
Were there any unexpected results or challenges during your research?
I don’t think we had appreciated before this study quite how high the vWF:Ag activity is in greyhound blood vs. non-greyhounds. As such, greyhounds are now our preferred donor for dogs with vWD.
Takeaways from this study
Our data, and that of others, suggests that cold SWB undoubtedly has a role in our arsenal of transfusion products for bleeding dogs. Indeed, clinics that use a reasonable volume of blood products would likely benefit from stocking this product in addition to traditional components (pRBCs and FFP). While many clotting factors are stable in this product, careful thought should be given to the duration of storage of the product vs. suitability for transfusion to dogs with different coagulation disturbances.
What future directions would you like to explore based on this study?
We also need to do similar studies with cat blood products.
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Dr Edwards and colleagues have published a similar and complementary study to ours that is well worth a read. Hemostatic capacity of canine chilled whole blood over time:
