Submitting canine blood for prothrombin time and partial thromboplastin time determinations

Area of Science:

• Veterinary Hematology
• Clinical Pathology
• Coagulation Diagnostics

Background:

• Veterinary practitioners frequently submit canine samples for coagulation testing.
• There is ongoing debate regarding optimal sample handling for accurate partial thromboplastin time (PTT) and prothrombin time (PT) results.

Purpose of the Study:

• To determine if whole blood or plasma is superior for canine PTT/PT analysis.
• To assess the necessity of refrigeration versus room temperature storage for canine coagulation samples.
• To establish the maximum acceptable time frame for sample analysis post-collection.

Main Methods:

• Canine plasma and whole blood samples were analyzed for PTT and PT.
• Samples were stored at either 4 degrees C or room temperature (20 degrees C).
• Sample integrity was assessed at various time points up to 48 hours post-collection.

Main Results:

• Reliable PTT and PT results were obtained from canine plasma stored at 4 degrees C for up to 48 hours, irrespective of immediate plasma separation.
• Room temperature storage yielded reliable PT results for up to 6 hours and PTT results for up to 24 hours.
• Immediate plasma separation enhanced PTT reliability at room temperature, potentially up to 48 hours.

Conclusions:

• Refrigeration at 4 degrees C is crucial for maintaining canine PTT/PT sample integrity for up to 48 hours.
• Room temperature storage is acceptable for short-term PT (6 hours) and PTT (24 hours) analysis.
• Plasma submission is generally preferred, especially for longer transport times or PTT analysis at room temperature.