Background: Most hematologic analyses are performed within a short time of blood sampling, but samples collected at the end of a week may have to be stored for up to 2 days. The stability of hematologic constituents is poorly documented.
Objective: The objective of this study was to compare the results of RBC, WBC and platelet counts, hemoglobin (Hgb) concentration, and MCV before and after storage of canine blood at room temperature for 24 and 48 hours.
Methods: One hundred fifty-two K3-EDTA canine blood specimens from 2 veterinary hospitals were analyzed within 4 hours of collection, then 24 and 48 hours later with a Coulter T540 hematology analyzer. Results were compared by Passing-Bablock agreement, difference plots, and according to their classification as normal or abnormal based on reference intervals.
Results: RBC count and Hgb concentration were stable for the duration of the study. Differences in WBC and platelet counts varied with the specimen, independently of the initial value. MCV increased consistently over the 2 days. However, only a few results were misclassified.
Conclusion: Whole blood specimens stored for up to 2 days at room temperature are suitable for cell counts and Hgb measurement. However, potential variations have to be known to avoid misinterpretations, especially near the decision limits.