THE EFFECTS OF EDTATUBE UNDERFILLING AND DELAYED ANALYSIS ON MEASURED MCV VALUES IN CANINE BLOOD SAMPLES

Abstract

This study investigated the impact of EDTA tube underfilling and delayed analysis on hematologic measurements in canine blood. Blood samples from 17 dogs were divided into four fill levels (100%, 50%, 25%, 12.5%) and analyzed at two timepoints, immediately after collection (t0) and after 24 hours (t24).

At T0, underfilling to 50% caused statistically significant but clinically acceptable differences in mean corpuscular volume (MCV) and other parameters. More severe underfilling (25% and 12.5%) caused larger deviations, but still within the reference change value (RCV). After 24 hours, MCV values increased across all fill levels due to swelling of the erytrocytes. At 25% and 12.5% fill, changes exceeded the RCV, indicating a clinically relevant change. Other parameters (HGB, HCT, MCHC, PLT) showed significant but mostly acceptable changes.

Conclusion: Half-filled EDTA tubes can still provide reliable results when analyzed immediately. However, delayed analysis, even when properly filled, may cause clinically misleading MCV values, highlighting the importance of prompt sample processing.