Comparison of small-volume tubes and vacuum blood tubes for complete blood count

INTRODUCTION: A complete blood count (CBC) is one of the most commonly requested clinical laboratory tests. Vacuum blood tubes are used routinely, and now, new small-volume tubes (SVTs) containing dipotassium ethylenediaminetetraacetic acid (K2EDTA) are also in use. The aim of this research was to compare SVTs with vacuum blood tubes for use in a CBC.
METHODS: Venous blood samples were taken from 40 healthy volunteers and were collected in BD Vacutainer (Becton, Dickinson and Company, Franklin Lakes, NJ, USA) K2EDTA tubes and BD Microtainer (Becton, Dickinson and Company, Franklin Lakes, NJ, USA) K2EDTA tubes. CBC parameters were analyzed using an ABX Pentra DF 120 device (Horiba, Ltd., Kyoto, Japan).
RESULTS: Red blood cells (RBC), hemoglobin (HGB), hematocrit (HCT), mean corpuscular hemoglobin (MCH), mean corpuscular hemoglobin concentration (MCHC), and basophil (BASO) levels were found to be statistically significantly higher, while platelet (PLT) levels were determined to be statistically significantly lower in the SVT analyses compared with those of the vacuum blood tubes. When the percentage difference was compared with the total allowable error, RBC, HGB, HCT, MCH, MCHC, red cell distribution width, white blood cell count, neutrophil, lymphocyte, monocyte, eosinophil, and BASO values demonstrated a general trend of positive bias, while PLT values demonstrated a general trend of negative bias on a Bland-Altman bias plot.
DISCUSSION AND CONCLUSION: The results of this study demonstrated that venous blood samples from SVTs generated a significant bias in the CBC results. In addition, clotted samples were observed more frequently among those collected in SVTs in this study. The design of SVTs may have an important and detrimental effect on the accuracy and efficacy of the results of a CBC.