Refrigerated Blood Platelets Could Save Dogs from Life-Threatening Bleeding, New Study Finds

Researchers discover that canine platelets can remain useful for up to three weeks in cold storage, potentially transforming emergency veterinary care.

A new study from Washington State University could change how veterinarians treat dogs suffering from dangerous bleeding. Researchers have found that blood platelets stored in a refrigerator for up to three weeks can help control bleeding in seriously ill dogs. The discovery could make an important treatment more widely available, particularly at veterinary hospitals that cannot maintain large blood banks. Although the study was relatively small, its findings offer encouraging evidence that a simpler method of storing platelets could save canine lives.

Why Blood Platelets Matter

When a dog suffers a serious injury or develops certain diseases, stopping internal or external bleeding can become a matter of life and death. Blood platelets are tiny cell fragments that help the body form clots. When a blood vessel is damaged, platelets gather at the injured area and help create a barrier that prevents further blood loss.

Some dogs develop a condition called thrombocytopenia, meaning they have dangerously low numbers of platelets in their blood. This can occur because of immune system disorders, cancer, severe infections or other medical problems. Affected dogs may develop bruising, bleeding from the gums, blood in their urine or potentially fatal internal bleeding.

In severe cases, veterinarians may need to give a platelet transfusion. Unfortunately, obtaining suitable platelet products has traditionally been difficult.

A Problem with Traditional Storage

Unlike red blood cells, which can be refrigerated for relatively long periods, platelet concentrates have traditionally been stored at room temperature. They also require continuous gentle movement to maintain their quality. Even under suitable conditions, their useful storage life is generally limited to approximately five days. This creates a serious problem for veterinary blood banks.

Platelet transfusions are not required every day, but when an emergency occurs, the product must be available immediately. Hospitals may struggle to maintain supplies because unused platelets expire quickly. Smaller veterinary clinics may have no access to platelet products at all. Researchers at Washington State University wanted to determine whether refrigeration could provide a practical alternative.

Testing Platelets Stored for Three Weeks

The research team, led by veterinary specialist Dr Jillian Haines, examined medical records from 24 dogs treated at the university’s veterinary teaching hospital. Between March 2022 and October 2024, these dogs received a total of 27 transfusions involving refrigerated platelet concentrates. The platelets had been stored at approximately 4°C for periods of up to 21 days.

Some dogs received transfusions because they were already bleeding. Others needed treatment before surgery or medical procedures that carried a substantial bleeding risk. The researchers examined bleeding severity before treatment and again one and four hours afterwards.

They also monitored platelet counts, transfusion reactions and whether the dogs survived to leave hospital. The findings were encouraging. Clinical improvement was recorded following 19 of the 27 transfusions, approximately 70%. Another seven transfusion events showed partial improvement. Average bleeding severity scores fell significantly within four hours of treatment. Importantly, no transfusion reactions were documented. Nineteen of the 24 dogs survived to hospital discharge.

Why the Results Are Important

One surprising finding was that platelet counts did not increase significantly following transfusion. This might initially seem disappointing, but the researchers explained that refrigerated platelets behave differently from traditionally stored platelets. Cold-stored platelets may disappear from circulation more quickly, while remaining effective at helping blood form clots.

For a dog experiencing dangerous bleeding, this immediate clotting ability may be more important than producing a lasting increase in platelet numbers. The study therefore suggests that refrigerated platelets could provide valuable short-term support during emergencies. There are also practical advantages.

Refrigerated platelets do not require continuous mechanical agitation, can be transported more easily and may present a lower risk of bacterial growth during storage. Most importantly, extending their usable storage period from approximately five days to three weeks could make it much easier for veterinary hospitals to maintain emergency supplies.

Important Limitations

Despite the promising findings, the researchers emphasised that further investigation is necessary. This was a retrospective study, meaning scientists examined existing treatment records rather than conducting a controlled clinical trial. The number of dogs was relatively small, and some animals received additional blood products or other treatments.

There was also no comparison group receiving traditionally stored platelets. Consequently, the researchers cannot establish precisely how much of the observed improvement resulted from the refrigerated platelets alone. Three dogs also experienced delayed bleeding after medical procedures, suggesting that some patients may require additional transfusions.

Future studies will need to investigate the best platelet doses, how long their effects last and whether storage periods beyond three weeks are possible.

A Potential Breakthrough for Veterinary Hospitals

Washington State University’s veterinary blood bank already maintains refrigerated platelet supplies. Dr Haines has also begun teaching the storage technique to veterinary professionals at other institutions. If further research confirms the benefits, the approach could eventually make platelet transfusions more accessible to veterinary hospitals around the world. This may be particularly valuable in areas where specialised blood-bank facilities are limited.

For dog owners, the research does not change how bleeding emergencies should be handled. Unexplained bleeding, unusual bruising or suspected internal haemorrhage still require immediate veterinary attention. However, it offers hope that veterinarians may soon have another practical option when conventional platelet products are unavailable.

Sometimes an important medical advance does not involve inventing a new medicine. It involves discovering a better way to preserve something veterinarians already know can save lives.

Primary Sources

1. Original peer-reviewed research

Monaco, S. A., Haines, J. M., Guess, S. C., Fiedler, S. M., and Wardrop, K. J. (2026).

The use of cold-stored platelets to provide hemostasis in dogs with thrombocytopenia.

Journal of Veterinary Internal Medicine, 40(5).

DOI: 10.1093/jvimsj/aalag262.

Read the complete open-access scientific paper

The paper confirms the sample size, clinical results, statistical findings and limitations. PubMed Central (PMC)

2. University research announcement — 3 November 2026

Washington State University, College of Veterinary Medicine.

WSU research could save dogs facing life-threatening bleeding.

Read the university’s original announcement

This provides additional information about the practical advantages of refrigerated platelets and their use at the university’s veterinary blood bank.