Evaluation of the HemoCue WBC DIFF system for Point-of-Care counting of total and differential white cells in pediatric samples

Point of Care Testing (POCT) accelerates the availability of critical labtest information that clinicians require to make rapid treatment decisions and monitor a patient's response. Especially, in pediatric environments, the ability to perform multiple tests with just a few drops of blood is precious. Total white blood cell (WBC) count and differentiation is an important tool in diagnosing infections. In an emergency care setting, both lymphocytopenia and the neutrophil to lymphocyte count ratio (NLCR) may serve as simple markers for discrimination between severe bacterial and viral infections and are better predictors of bacteremia than routine parameters like CRP level, total WBC and neutrophil count (1, 2). Recently, HemoCue launched a POCT analyser (HemoCue WBC DIFF system), able to count and differentiate white blood cells, including differentiation (DIFF, absolute and percentage) in neutrophil, lymphocyte, monocyte, eosinophil and basophil counts in capillary or venous whole blood (3). The Hemocue WBC DIFF technique is based on cell counting using a microcuvette with a small volume of only 10 μl of blood. The blood sample is drawn into the cavity of the microcuvette by capillary force. A cell-lysing agent will hemolyse the red blood cells and a staining agent will stain the white blood cells. The microcuvette is placed in the analyser and the numbers of white blood cells are counted by image analysis (4). This study was undertaken to assess the reliability of the HemoCue WBC DIFF system fulfilling the medical and clinical requirements regarding to accuracy and precision according to CLSI EP9-A2 (5) of measurement for total white blood cell and 5-parts differential count in capillary pediatric samples.