Study examines 14-day cold storage for canine platelet units: full analysis

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A newly published prospective experimental study is pushing forward a longstanding question in veterinary transfusion medicine: how long canine platelet concentrate can be stored without becoming clinically irrelevant. In the new paper, published in the March-April 2026 issue of the Journal of Veterinary Emergency and Critical Care, investigators reported that canine platelet concentrate stored at 4°C for 14 days maintained stable counts, acceptable metabolic parameters, and overall viability, even as platelet function declined in an agonist-dependent way. (pubmed.ncbi.nlm.nih.gov)

The work comes against the backdrop of a familiar logistical problem for veterinary blood banks. Platelet products are difficult to keep on hand because conventional storage windows are short, and platelets are especially vulnerable to so-called storage lesions over time. Earlier canine studies found that room-temperature platelet concentrates could retain viability for several days, but function progressively worsened, and a 2020 quality-control study documented declining pH, rising lactate, reduced swirling, and other deterioration markers by Day 5 under standard storage conditions. (pubmed.ncbi.nlm.nih.gov)

In the new study, six canine platelet concentrate units were stored at 4°C without agitation and tested on Days 0, 5, 7, 9, 12, and 14. The team assessed hematologic and metabolic variables, aggregation, activation markers, phosphatidylserine externalization, and aerobic and anaerobic bacterial culture. Platelet counts remained above 500,000/µL throughout storage, lactate rose from a median 2.1 mmol/L on Day 0 to 9.6 mmol/L on Day 14, and all pH values stayed above 7.1. Flow cytometry did not show a significant drop in overall viability over time. (pubmed.ncbi.nlm.nih.gov)

Function was the more complicated story. Aggregation responses to ADP were minimal, collagen did not produce robust aggregation during the storage period, and thrombin-induced aggregation remained comparatively stronger through Day 12. The authors also found increased alpha-granule secretion late in storage with some stimuli, decreased secretion after Day 7 with thrombin stimulation, and variable P-selectin and Annexin V expression patterns. In other words, the platelets did not simply become nonfunctional across the board; their responsiveness shifted depending on how function was measured. One unit also showed bacterial growth on Day 14, an important caution point for anyone thinking about extending shelf life in practice. (pubmed.ncbi.nlm.nih.gov)

That nuance fits with the broader literature. Older canine studies suggested cold conditions could preserve some platelet characteristics longer than room-temperature storage, and more recent work from Washington State University reported that platelet additive solutions combined with 4°C storage may help prolong functional canine platelet concentrate even further, out to 21 days in an ex vivo setting. At the same time, the field still lacks the kind of in vivo outcome data that would tell clinicians whether a product that looks acceptable in the lab will meaningfully control bleeding in patients. (pubmed.ncbi.nlm.nih.gov)

The authors are well positioned within that translational space. Farrell, Epstein, and Nguyen are affiliated with the University of California, Davis, and Li is now at North Carolina State University, where his faculty profile highlights platelet biology, immunothrombosis, and translational research aimed at benefiting clinical patients. That doesn't change the data, but it does underscore that this study sits within a broader effort to make platelet science more usable at the bedside, or cage-side, in emergency and critical care. (pubmed.ncbi.nlm.nih.gov)

Why it matters: For veterinary professionals, the practical implication is inventory management as much as platelet biology. If cold storage can safely extend shelf life beyond the narrow room-temperature window, blood banks and referral hospitals may be better able to stock platelet products for thrombocytopenic or actively bleeding dogs without the same level of waste and shortage pressure. But this paper should be read as a feasibility and characterization study, not a green light for broad protocol changes. The preserved viability and acceptable pH are encouraging, yet the agonist-dependent loss of function and the Day-14 bacterial finding mean product handling, quality control, and clinical endpoint studies remain central before widespread adoption. (pubmed.ncbi.nlm.nih.gov)

What to watch: The next inflection point will be in vivo transfusion data, along with any follow-on work comparing cold-stored units with standard room-temperature products or additive-solution formulations on hemostatic efficacy, post-transfusion survival, and contamination risk. If those data are favorable, cold-stored canine platelet concentrate could become a more realistic option for hospitals trying to balance readiness, cost, and patient care. (pubmed.ncbi.nlm.nih.gov)